Document socket.timeout as OSError subclass and TimeoutError alias

socket.timeout has been a subclass of OSError since Python 3.3 and
a deprecated alias of TimeoutError since Python 3.10.

Author: julianz-

cheroot/connections.py

@@ -370,6 +370,7 @@ def _accept_conn(self, server_socket):
         """Accept the connection."""
         try:
             sock, addr = server_socket.accept()
+        # socket.timeout: OSError subclass (3.3+), TimeoutError alias (3.10+)
         except socket.timeout:
             return None
         except OSError as exc: