unused-courotine should trigger when using a coroutine call as a condition without awaiting it

[jakkdl]

Feature Extend unused-coroutine to also encompass directly using the unawaited result with if/while, or perhaps also in other instances where it's used as a condition such as boolean operations etc. Or since the return value technically is used, introduce another error code.

Pitch Currently no warning is raised for the following code:

async def foo() -> bool:
    return False
if foo():
    print("foo is true!")

because the return value of the coroutine technically is used. But it's very clearly an error, will give a RuntimeWarning, and bool(foo()) always evaluates to True. I also have a hard time coming up with reasonable scenarios where the above functionality is desired, other than perhaps some weird logic for figuring out if a function is async or not - but in that case the object should be a union of those types and the type checker should be able to handle it.