Document missing methods of ssl.SSLObject (#19400)

Co-authored-by: Rémi Lapeyre <[email protected]>

Author: Rémi Lapeyre

Doc/library/ssl.rst

@@ -2486,14 +2486,17 @@ provided.
    - :meth:`~SSLSocket.read`
    - :meth:`~SSLSocket.write`
    - :meth:`~SSLSocket.getpeercert`
+   - :meth:`~SSLSocket.selected_alpn_protocol`
    - :meth:`~SSLSocket.selected_npn_protocol`
    - :meth:`~SSLSocket.cipher`
    - :meth:`~SSLSocket.shared_ciphers`
    - :meth:`~SSLSocket.compression`
    - :meth:`~SSLSocket.pending`
    - :meth:`~SSLSocket.do_handshake`
+   - :meth:`~SSLSocket.verify_client_post_handshake`
    - :meth:`~SSLSocket.unwrap`
    - :meth:`~SSLSocket.get_channel_binding`
+   - :meth:`~SSLSocket.version`
 
    When compared to :class:`SSLSocket`, this object lacks the following
    features: