Add missing files for API docs (#15622)

`docs_main.cr` needs explicitly listing files for API docs, and we keep forgetting to add new ones.

Author: straight-shoota

src/docs_main.cr

@@ -4,6 +4,8 @@
 
 require "./annotations"
 require "./big"
+require "./big/json"
+require "./big/yaml"
 require "./compiler/crystal/macros"
 require "./compress/**"
 require "./crypto/**"
@@ -26,7 +28,8 @@ require "./openssl"
 require "./process"
 require "./regex"
 require "./socket"
-require "./spec/**"
+require "./spec"
+require "./spec/helpers/**"
 require "./string/**"
 require "./weak_ref"
 require "./xml"
@@ -42,6 +45,7 @@ require "./file_utils"
 require "./ini"
 require "./levenshtein"
 require "./log"
+require "./log/json"
 require "./log/spec"
 require "./option_parser"
 require "./path"
@@ -53,9 +57,11 @@ require "./string_scanner"
 require "./unicode/unicode"
 require "./uri"
 require "./uri/json"
+require "./uri/yaml"
 require "./uri/params/serializable"
 require "./uuid"
 require "./uuid/json"
+require "./uuid/yaml"
 require "./syscall"
 require "./system/*"
 require "./wait_group"