docs: fix links in 4.x docs

Fix #6081

Author: vkarpov15

docs/connections.jade

@@ -49,7 +49,7 @@ block content
     }, 60000);
 
   :markdown
-    To disable buffering, turn off the [`bufferCommands` option on your schema](http://mongoosejs.com/docs/guide.html#bufferCommands).
+    To disable buffering, turn off the [`bufferCommands` option on your schema](./guide.html#bufferCommands).
     If you have `bufferCommands` on and your connection is hanging, try turning
     `bufferCommands` off to see if you haven't opened a connection properly.
 
@@ -92,7 +92,7 @@ block content
 
   h3#callback Callback
   :markdown
-    The `connect()` function also accepts a callback parameter and returns a [promise](http://mongoosejs.com/docs/promises.html).
+    The `connect()` function also accepts a callback parameter and returns a [promise](./promises.html).
   :js
     mongoose.connect(uri, options, function(error) {
       // Check error in initial connection. There is no 2nd param to the callback.

docs/documents.jade

@@ -22,7 +22,7 @@ block content
       });
     });
   :markdown
-    You can also use [`.set()`](http://mongoosejs.com/docs/api.html#document_Document-set)
+    You can also use [`.set()`](./api.html#document_Document-set)
     to modify documents. Under the hood, `tank.size = 'large';` becomes `tank.set({ size: 'large' })`.
   :js
     Tank.findById(id, function (err, tank) {
@@ -51,7 +51,7 @@ block content
     });
   :markdown
     The `findAndUpdate/Remove` static methods all make a change to at most one document, and return it with just one call to the database. There [are](./api.html#model_Model.findByIdAndRemove) [several](./api.html#model_Model.findOneAndUpdate) [variations](./api.html#model_Model.findOneAndRemove) on the [findAndModify](http://www.mongodb.org/display/DOCS/findAndModify+Command) theme. Read the [API](./api.html) docs for more detail.
-    
+
     _Note that `findAndUpdate/Remove` do *not* execute any hooks or validation before making the change in the database. You can use the [`runValidators` option](/docs/validation.html#update-validators) to access a limited subset of document validation. However, if you need hooks and full document validation, first query for the document and then `save()` it._
 
   h3 Validating
@@ -61,7 +61,7 @@ block content
   h3 Overwriting
   :markdown
     You can overwrite an entire document using `.set()`. This is handy if you
-    want to change what document is being saved in [middleware](http://mongoosejs.com/docs/middleware.html).
+    want to change what document is being saved in [middleware](./docs/middleware.html).
   :js
     Tank.findById(id, function (err, tank) {
       if (err) return handleError(err);

docs/faq.jade

@@ -95,7 +95,7 @@ block content
   :markdown
     **A**. This is a performance optimization. These empty objects are not saved
     to the database, nor are they in the result `toObject()`, nor do they show
-    up in `JSON.stringify()` output unless you turn off the [`minimize` option](http://mongoosejs.com/docs/guide.html#minimize).
+    up in `JSON.stringify()` output unless you turn off the [`minimize` option](./guide.html#minimize).
 
     The reason for this behavior is that Mongoose's change detection
     and getters/setters are based on [`Object.defineProperty()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty).
@@ -104,11 +104,11 @@ block content
     mongoose defines properties on the `Model` prototype when the model is compiled.
     Because mongoose needs to define getters and setters for `nested.prop`, `nested`
     must always be defined as an object on a mongoose document, even if `nested`
-    is undefined on the underlying [POJO](http://mongoosejs.com/docs/guide.html#minimize).
+    is undefined on the underlying [POJO](./guide.html#minimize).
 
   hr#arrow-functions
   :markdown
-    **Q**. I'm using an arrow function for a [virtual](http://mongoosejs.com/docs/guide.html#virtuals), getter/setter, or [method](http://mongoosejs.com/docs/guide.html#methods) and the value of `this` is wrong.
+    **Q**. I'm using an arrow function for a [virtual](./guide.html#virtuals), getter/setter, or [method](./guide.html#methods) and the value of `this` is wrong.
 
     **A**. Arrow functions [handle the `this` keyword much differently than conventional functions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#No_binding_of_this).
     Mongoose getters/setters depend on `this` to give you access to the document that you're writing to, but this functionality does not work with arrow functions. Do **not** use arrow functions for mongoose getters/setters unless do not intend to access the document in the getter/setter.
@@ -215,7 +215,7 @@ block content
     **Q**. All function calls on my models hang, what am I doing wrong?
 
     **A**. By default, mongoose will buffer your function calls until it can
-    connect to MongoDB. Read the [buffering section of the connection docs](http://mongoosejs.com/docs/connections.html#buffering)
+    connect to MongoDB. Read the [buffering section of the connection docs](./connections.html#buffering)
     for more information.
 
   hr#enable_debugging

docs/guide.jade

@@ -694,7 +694,7 @@ block content
 
   h4#timestamps option: timestamps
   :markdown
-    If set `timestamps`, mongoose assigns `createdAt` and `updatedAt` fields to your schema, the type assigned is [Date](http://mongoosejs.com/docs/api.html#schema-date-js).
+    If set `timestamps`, mongoose assigns `createdAt` and `updatedAt` fields to your schema, the type assigned is [Date](./api.html#schema-date-js).
 
     By default, the name of two fields are `createdAt` and `updatedAt`, customize the field name by setting `timestamps.createdAt` and `timestamps.updatedAt`.
   :js

docs/middleware.jade

@@ -28,9 +28,9 @@ block content
 
     Aggregate middleware is for `MyModel.aggregate()`. Aggregate middleware
     executes when you call `exec()` on an aggregate object.
-    In aggregate middleware, `this` refers to the [aggregation object](http://mongoosejs.com/docs/api.html#model_Model.aggregate).
+    In aggregate middleware, `this` refers to the [aggregation object](./api.html#model_Model.aggregate).
 
-    * [aggregate](http://mongoosejs.com/docs/api.html#model_Model.aggregate)
+    * [aggregate](./api.html#model_Model.aggregate)
 
     Model middleware is supported for the following model functions.
     In model middleware functions, `this` refers to the model.

docs/populate.jade

@@ -214,7 +214,7 @@ block content
     populate them using the [Model.populate()](./api.html#model_Model.populate)
     method available in **mongoose >= 3.6**. This is what `document#populate()`
     and `query#populate()` use to populate documents.
-  
+
   h3#deep-populate Populating across multiple levels
   :markdown
     Say you have a user schema which keeps track of the user's friends.
@@ -235,7 +235,7 @@ block content
         // Get friends of friends - populate the 'friends' array for every friend
         populate: { path: 'friends' }
       });
-  
+
   h3#cross-db-populate Populating across Databases
   :markdown
     Let's say you have a schema representing events, and a schema representing
@@ -256,14 +256,14 @@ block content
   :js
     var db1 = mongoose.createConnection('localhost:27000/db1');
     var db2 = mongoose.createConnection('localhost:27001/db2');
-    
+
     var Event = db1.model('Event', eventSchema);
     var Conversation = db2.model('Conversation', conversationSchema);
   :markdown
     In this situation, you will **not** be able to `populate()` normally.
     The `conversation` field will always be null, because `populate()` doesn't
     know which model to use. However,
-    [you can specify the model explicitly](http://mongoosejs.com/docs/api.html#model_Model.populate).
+    [you can specify the model explicitly](./api.html#model_Model.populate).
   :js
     Event.
       find().
@@ -286,9 +286,9 @@ block content
         item: { type: ObjectId, refPath: 'connections.kind' }
       }]
     });
-    
+
     var organizationSchema = new Schema({ name: String, kind: String });
-    
+
     var User = mongoose.model('User', userSchema);
     var Organization = mongoose.model('Organization', organizationSchema);
   :markdown
@@ -320,17 +320,17 @@ block content
         // doc.connections[0].item is a User doc
         // doc.connections[1].item is an Organization doc
       });
-    
+
   h3#populate-virtuals Populate Virtuals
   :markdown
     _New in 4.5.0_
-    
+
     So far you've only populated based on the `_id` field. However, that's
     sometimes not the right choice.
     In particular, [arrays that grow without bound are a MongoDB anti-pattern](https://docs.mongodb.com/manual/tutorial/model-referenced-one-to-many-relationships-between-documents/).
     Using mongoose virtuals, you can define more sophisticated relationships
     between documents.
-  
+
   :js
     var PersonSchema = new Schema({
       name: String,
@@ -348,10 +348,10 @@ block content
       // an array. `justOne` is false by default.
       justOne: false
     });
-    
+
     var Person = mongoose.model('Person', PersonSchema);
     var Band = mongoose.model('Band', BandSchema);
-    
+
     /**
      * Suppose you have 2 bands: "Guns N' Roses" and "Motley Crue"
      * And 4 people: "Axl Rose" and "Slash" with "Guns N' Roses", and
@@ -360,24 +360,24 @@ block content
     Band.find({}).populate('members').exec(function(error, bands) {
       /* `bands.members` is now an array of instances of `Person` */
     });
-  
+
   :markdown
     Keep in mind that virtuals are _not_ included in `toJSON()` output by
     default. If you want populate virtuals to show up when using functions
     that rely on `JSON.stringify()`, like Express'
     [`res.json()` function](http://expressjs.com/en/4x/api.html#res.json),
     set the `virtuals: true` option on your schema's `toJSON` options.
-  
+
   :js
     // Set `virtuals: true` so `res.json()` works
     var BandSchema = new Schema({
       name: String
     }, { toJSON: { virtuals: true } });
-  
+
   :markdown
     If you're using populate projections, make sure `foreignField` is included
     in the projection.
-    
+
   :js
     Band.
       find({}).

docs/queries.jade

@@ -28,7 +28,7 @@ block content
     })
   :markdown
     Here we see that the query was executed immediately and the results passed to our callback. All callbacks in Mongoose use the pattern:
-    `callback(error, result)`. If an error occurs executing the query, the `error` parameter will contain an error document, and `result` 
+    `callback(error, result)`. If an error occurs executing the query, the `error` parameter will contain an error document, and `result`
     will be null. If the query is successful, the `error` parameter will be null, and the `result` will be populated with the results of the query.
   .important
     :markdown
@@ -77,24 +77,24 @@ block content
       exec(callback);
 
   :markdown
-    A full list of [Query helper functions can be found in the API docs](http://mongoosejs.com/docs/api.html#query-js).
+    A full list of [Query helper functions can be found in the API docs](./api.html#query-js).
 
   h3#setters
   :markdown
     Setters are not executed by default in 4.x. For example, if you lowercase emails in your schema:
-  
+
   :js
     var personSchema = new Schema({
       email: {
         type: String,
         lowercase: true
       }
     });
-  
+
   :markdown
     Mongoose will **not** automatically lowercase the email in your queries, so `Person.find({ email: '[email protected]' })` would return no results.
     Use the `runSettersOnQuery` option to turn on this behavior:
-  
+
   :js
     var personSchema = new Schema({
       email: {

docs/schematypes.jade

@@ -17,7 +17,7 @@ block content
     a(href="./api.html#query-js") queries
     |  and other general characteristics for 
     a(href="./api.html#schema-string-js") Strings
-    |  and 
+    |  and
     a(href="./api.html#schema-number-js") Numbers
     |. Check out their respective API documentation for more detail.
   p
@@ -88,7 +88,7 @@ block content
     var schema1 = new Schema({
       test: String // `test` is a path of type String
     });
-    
+
     var schema2 = new Schema({
       test: { type: String } // `test` is a path of type string
     });
@@ -108,14 +108,14 @@ block content
     types.
   h5 All Schema Types
   :markdown
-    * `required`: boolean or function, if true adds a [required validator](http://mongoosejs.com/docs/validation.html#built-in-validators) for this property
+    * `required`: boolean or function, if true adds a [required validator](./validation.html#built-in-validators) for this property
     * `default`: Any or function, sets a default value for the path. If the value is a function, the return value of the function is used as the default.
     * `select`: boolean, specifies default [projections](https://docs.mongodb.com/manual/tutorial/project-fields-from-query-results/) for queries
-    * `validate`: function, adds a [validator function](http://mongoosejs.com/docs/validation.html#built-in-validators) for this property
+    * `validate`: function, adds a [validator function](./validation.html#built-in-validators) for this property
     * `get`: function, defines a custom getter for this property using [`Object.defineProperty()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty).
     * `set`: function, defines a custom setter for this property using [`Object.defineProperty()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty).
-    * `alias`: string, mongoose >= 4.10.0 only. Defines a [virtual](http://mongoosejs.com/docs/guide.html#virtuals) with the given name that gets/sets this path.
-    
+    * `alias`: string, mongoose >= 4.10.0 only. Defines a [virtual](./guide.html#virtuals) with the given name that gets/sets this path.
+
   :js
     var numberSchema = new Schema({
       integerOnly: {
@@ -125,23 +125,23 @@ block content
         alias: 'i'
       }
     });
-    
+
     var Number = mongoose.model('Number', numberSchema);
-    
+
     var doc = new Number();
     doc.integerOnly = 2.001;
     doc.integerOnly; // 2
     doc.i; // 2
     doc.i = 3.001;
     doc.integerOnly; // 3
     doc.i; // 3
-  
+
   h5 Indexes
   p
   :markdown
     You can also define [MongoDB indexes](https://docs.mongodb.com/manual/indexes/)
     using schema type options.
-   
+
   :markdown
     * `index`: boolean, whether to define an [index](https://docs.mongodb.com/manual/indexes/) on this property.
     * `unique`: boolean, whether to define a [unique index](https://docs.mongodb.com/manual/core/index-unique/) on this property.
@@ -160,14 +160,14 @@ block content
     * `lowercase`: boolean, whether to always call `.toLowerCase()` on the value
     * `uppercase`: boolean, whether to always call `.toUpperCase()` on the value
     * `trim`: boolean, whether to always call `.trim()` on the value
-    * `match`: RegExp, creates a [validator](http://mongoosejs.com/docs/validation.html) that checks if the value matches the given regular expression
-    * `enum`: Array, creates a [validator](http://mongoosejs.com/docs/validation.html) that checks if the value is in the given array.
+    * `match`: RegExp, creates a [validator](./validation.html) that checks if the value matches the given regular expression
+    * `enum`: Array, creates a [validator](./validation.html) that checks if the value is in the given array.
 
   h5 Number
   :markdown
-    * `min`: Number, creates a [validator](http://mongoosejs.com/docs/validation.html) that checks if the value is greater than or equal to the given minimum.
-    * `max`: Number, creates a [validator](http://mongoosejs.com/docs/validation.html) that checks if the value is less than or equal to the given maximum.
-  
+    * `min`: Number, creates a [validator](./validation.html) that checks if the value is greater than or equal to the given minimum.
+    * `max`: Number, creates a [validator](./validation.html) that checks if the value is less than or equal to the given maximum.
+
   h5 Date
   :markdown
     * `min`: Date
@@ -195,7 +195,7 @@ block content
     var Any = new Schema({ any: Object });
     var Any = new Schema({ any: Schema.Types.Mixed });
   p
-    | Since it is a schema-less type, you can change the value to anything else you like, but Mongoose loses the ability to auto detect and save those changes. To "tell" Mongoose that the value of a Mixed type has changed, call the 
+    | Since it is a schema-less type, you can change the value to anything else you like, but Mongoose loses the ability to auto detect and save those changes. To "tell" Mongoose that the value of a Mixed type has changed, call the
     code .markModified(path)
     |  method of the document passing the path to the Mixed type you just changed.
   :js
@@ -204,7 +204,7 @@ block content
     person.save(); // anything will now get saved
   h4#objectids ObjectIds
   p
-    | To specify a type of ObjectId, use 
+    | To specify a type of ObjectId, use
     code Schema.Types.ObjectId
     |  in your declaration.
   :js
@@ -214,9 +214,9 @@ block content
     // or just Schema.ObjectId for backwards compatibility with v2
   h4#arrays Arrays
   p
-    | Provide creation of arrays of 
+    | Provide creation of arrays of
     a(href="./api.html#schema_Schema.Types") SchemaTypes
-    |  or 
+    |  or
     a(href="./subdocs.html") Sub-Documents
     |.
   :js
@@ -229,9 +229,9 @@ block content
       // ... etc
     });
   p
-    | Note: specifying an empty array is equivalent to 
+    | Note: specifying an empty array is equivalent to
     code Mixed
-    |. The following all create arrays of 
+    |. The following all create arrays of
     code Mixed
     |:
   :js
@@ -268,18 +268,18 @@ block content
     });
   h3#customtypes Creating Custom Types
   p
-    | Mongoose can also be extended with custom SchemaTypes. Search the 
+    | Mongoose can also be extended with custom SchemaTypes. Search the
     a(href="http://plugins.mongoosejs.com") plugins
-    |  site for compatible types like 
+    |  site for compatible types like
     a(href="https://github.com/aheckmann/mongoose-long") mongoose-long
     | , 
     a(href="https://github.com/vkarpov15/mongoose-int32") mongoose-int32
-    |  and 
+    |  and
     a(href="https://github.com/aheckmann/mongoose-function") other
-    | 
+    |
     a(href="https://github.com/OpenifyIt/mongoose-types") types
     |.
-    
+
   h3#path The `schema.path()` Function
   :markdown
     The `schema.path()` function returns the instantiated schema type for a