iscoroutinefunction should use TypeIs

One of the things I find myself writing a lot is

if iscoroutinefunction(myfunction):
    do_something_with_async(myfunction)
else:
    do_something_with_just_sync(myfunction)

however the else block doesn't narrow the type to non-awaitable. Shouldn't it? Some of the other is... functions in inspect seem to use TypeIs as well.

定位 inspect.iscoroutinefunction 的 typeshed 存根条目，并将其注解与其他使用 TypeIs 的 inspect is... 函数进行比较。更新该注解，使两个分支都按所述方式进行收窄，然后运行相关的类型检查测试，以确认 coroutine 函数和 else 分支都能正确收窄。