gh-101100: Fix sphinx warnings in types module (#102274)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Doc/library/types.rst

@@ -486,7 +486,7 @@ Coroutine Utility Functions
    The generator-based coroutine is still a :term:`generator iterator`,
    but is also considered to be a :term:`coroutine` object and is
    :term:`awaitable`.  However, it may not necessarily implement
-   the :meth:`__await__` method.
+   the :meth:`~object.__await__` method.
 
    If *gen_func* is a generator function, it will be modified in-place.