[3.9] bpo-45772: socket.socket should be a class instead of a function (GH-23960...

[3.9] bpo-45772: socket.socket should be a class instead of a function (GH-23960) (GH-29543)

* [bpo-45772](): socket.socket should be a class instead of a function

Currently `socket.socket` is documented as a function, but it is really
a class (and thus has function-like usage to construct an object). This
correction would ensure that Python projects that are interlinking
Python's documentation can properly locate `socket.socket` as a type.
(cherry picked from commit 4c792f39e688b11c7c19e411ed4f76a7baa44638)

Co-authored-by: Hong Xu <hong@topbug.net>
Automerge-Triggered-By: GH:asvetlov