add TypeGuard to coroutines.iscoroutine

Author: KotlinIsland

stdlib/asyncio/coroutines.pyi

@@ -1,7 +1,12 @@
+import collections.abc
+import types
 from typing import Any, Callable, TypeVar
+from typing_extensions import TypeGuard
 
 _F = TypeVar("_F", bound=Callable[..., Any])
 
+_COROUTINE_TYPE = types.CoroutineType | types.GeneratorType | collections.abc.Coroutine
+
 def coroutine(func: _F) -> _F: ...
 def iscoroutinefunction(func: object) -> bool: ...
-def iscoroutine(obj: object) -> bool: ...
+def iscoroutine(obj: object) -> TypeGuard[_COROUTINE_TYPE]: ...