Annotations for psycopg2.ConnectionInfo

These annotations come from the documentation here:

https://www.psycopg.org/docs/extensions.html#psycopg2.extensions.ConnectionInfo
If there was doubt, I referred to the libpq documentation cited by
psycopg2's docs.

I wasn't completely sure about `dsn_parameters`. Psycopg2's docs list it
as an `dict`, and the example suggests it's a `dict[str, str]` at that.
From psycopg2's source I found

    https://github.com/psycopg/psycopg2/blob/1d3a89a0bba621dc1cc9b32db6d241bd2da85ad1/psycopg/conninfo_type.c#L183-L206

which is implemented here:

    https://github.com/psycopg/psycopg2/blob/1d3a89a0bba621dc1cc9b32db6d241bd2da85ad1/psycopg/utils.c#L251-L279

I'm no expert in CPython's API, but this looks to me like it's building
a `dict[str, str]`.

Additionally, the libpq docs

https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PQCONNINFO
https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PQCONNDEFAULTS

show that the underlying data just consists of strings.

Additionally, I'm pretty sure from this chunk of source

    https://github.com/psycopg/psycopg2/blob/1d3a89a0bba621dc1cc9b32db6d241bd2da85ad1/psycopg/conninfo_type.c#L581-L598

That `ConnectionInfo.__init__` takes one positional-only argument, which
must be a `psycopg2.connection`. But I don't think users are intended to
be constructing this type, so I've not added that annotation.

Author: DMRobertson

stubs/psycopg2/psycopg2/_psycopg.pyi

@@ -157,27 +157,27 @@ class Column:
     def __setstate__(self, state): ...
 
 class ConnectionInfo:
-    backend_pid: Any
-    dbname: Any
-    dsn_parameters: Any
-    error_message: Any
-    host: Any
-    needs_password: Any
-    options: Any
-    password: Any
-    port: Any
-    protocol_version: Any
-    server_version: Any
-    socket: Any
-    ssl_attribute_names: Any
-    ssl_in_use: Any
-    status: Any
-    transaction_status: Any
-    used_password: Any
-    user: Any
+    backend_pid: int
+    dbname: str
+    dsn_parameters: dict
+    error_message: str | None
+    host: str
+    needs_password: bool
+    options: str
+    password: str
+    port: int
+    protocol_version: int
+    server_version: int
+    socket: int
+    ssl_attribute_names: list[str]
+    ssl_in_use: bool
+    status: int
+    transaction_status: int
+    used_password: bool
+    user: str
     def __init__(self, *args, **kwargs) -> None: ...
-    def parameter_status(self, *args, **kwargs): ...
-    def ssl_attribute(self, *args, **kwargs): ...
+    def parameter_status(self, name: str) -> str | None: ...
+    def ssl_attribute(self, name: str) -> str | None: ...
 
 class DataError(psycopg2.DatabaseError): ...
 class DatabaseError(psycopg2.Error): ...