Apply suggestion from @gpshead

Author: gpshead

Doc/library/ssl.rst

@@ -1899,6 +1899,8 @@ to speed up repeated connections from the same clients.
 
    The return type of :meth:`SSLContext.wrap_socket`, defaults to
    :class:`SSLSocket`. The attribute can be assigned to on instances of
+   :class:`SSLContext` in order to return a custom subclass of
+   :class:`SSLSocket`.
    :class:`SSLContext` or overridden on subclasses of :class:`SSLContext`
    in order to return a custom subclass of :class:`SSLSocket`.