docs/library/ssl: Change wrap_socket args keyfile/certfile to key/cert.

So they match the code in extmod/modssl_*.c.

Signed-off-by: Damien George <damien@micropython.org>

docs/library/ssl.rst

@@ -13,7 +13,7 @@ facilities for network sockets, both client-side and server-side.
 Functions
 ---------
 
-.. function:: ssl.wrap_socket(sock, server_side=False, keyfile=None, certfile=None, cert_reqs=CERT_NONE, cadata=None, server_hostname=None, do_handshake=True)
+.. function:: ssl.wrap_socket(sock, server_side=False, key=None, cert=None, cert_reqs=CERT_NONE, cadata=None, server_hostname=None, do_handshake=True)
 
     Wrap the given *sock* and return a new wrapped-socket object.  The implementation
     of this function is to first create an `SSLContext` and then call the `SSLContext.wrap_socket`