Use TypeAlias for type aliases where possible, part II (#7667)

stubs/waitress/waitress/wasyncore.pyi

@@ -3,10 +3,11 @@ from io import BytesIO
 from logging import Logger
 from socket import socket
 from typing import Any
+from typing_extensions import TypeAlias
 
 from . import compat as compat, utilities as utilities
 
-_socket = socket
+_socket: TypeAlias = socket
 
 socket_map: Mapping[int, socket]
 map: Mapping[int, socket]