Rework socket (#5545)

* Extract _socket.pyi from socket.pyi.
* Extract _socket.socket from socket.socket.
* Fix socket.family annotation.
* Annotate SocketIO properly.
* SocketType is an alias of _socket.socket.
* Sort items in socket.pyi in the same order as in socket.py.
* Remove socket.EINTR.
* Use _typeshed.WriteableBuffer instead of custom alias.
* Add errorTab (Windows only).
* Add _socket.dup().
* Mark positional-only argments.
* Remove constructors from socket exceptions.
* socket.timeout is an alias for TimeoutError, starting with Python 3.10.
* Use PEP 604 in changed lines.
* Add alias for fileno arguments.
* getaddrinfo() port can be bytes.
* Explicitly override some SSLSocket methods.
* Allow ReadableBuffer in _CMSG arguments.

stdlib/asyncio/windows_events.pyi

@@ -1,5 +1,6 @@
 import socket
 import sys
+from _typeshed import WriteableBuffer
 from typing import IO, Any, Callable, ClassVar, List, NoReturn, Optional, Tuple, Type
 
 from . import events, futures, proactor_events, selector_events, streams, windows_utils
@@ -45,8 +46,8 @@ class IocpProactor:
     def select(self, timeout: Optional[int] = ...) -> List[futures.Future[Any]]: ...
     def recv(self, conn: socket.socket, nbytes: int, flags: int = ...) -> futures.Future[bytes]: ...
     if sys.version_info >= (3, 7):
-        def recv_into(self, conn: socket.socket, buf: socket._WriteBuffer, flags: int = ...) -> futures.Future[Any]: ...
-    def send(self, conn: socket.socket, buf: socket._WriteBuffer, flags: int = ...) -> futures.Future[Any]: ...
+        def recv_into(self, conn: socket.socket, buf: WriteableBuffer, flags: int = ...) -> futures.Future[Any]: ...
+    def send(self, conn: socket.socket, buf: WriteableBuffer, flags: int = ...) -> futures.Future[Any]: ...
     def accept(self, listener: socket.socket) -> futures.Future[Any]: ...
     def connect(self, conn: socket.socket, address: bytes) -> futures.Future[Any]: ...
     if sys.version_info >= (3, 7):