bpo-34802: Fix asyncio.iscoroutine() docs (GH-9611)

Author: 1st1

Doc/library/asyncio-task.rst

@@ -924,8 +924,7 @@ enforced.
  Return ``True`` if *obj* is a :ref:`coroutine object <coroutine>`.
 
  This method is different from :func:`inspect.iscoroutine` because
- it returns ``True`` for generator-based coroutines decorated with
- :func:`@coroutine <coroutine>`.
+ it returns ``True`` for generator-based coroutines.
 
 .. function:: iscoroutinefunction(func)