Fix a minor typo. (#1032) (#1036)

(cherry picked from commit dd9a0a1)

Author: warsaw

Doc/library/asyncio-protocol.rst

@@ -381,7 +381,7 @@ The following callbacks are called on :class:`Protocol` instances:
 
 .. method:: Protocol.eof_received()
 
-   Calls when the other end signals it won't send any more data
+   Called when the other end signals it won't send any more data
    (for example by calling :meth:`write_eof`, if the other end also uses
    asyncio).