Make filter() use TypeGuard

[JelleZijlstra]

This will probably require a lot of overloads.

[layday]

Does it not require just the one extra overload?

@overload
def __init__(self, __function: Callable[[_S], TypeGuard[_T]], __iterable: Iterable[_S]) -> None: ...

[sobolevn]

Related https://github.com/python/mypy/blob/05f38571f1b7af46dbadaeba0f74626d3a9e07c9/test-data/unit/check-typeguard.test#L250-L274

I think we can try to add this feature based on this existing test.
I will make an attempt to fix this.

[AlexWaygood]

Fixed by #5661

[laundmo]

Fixed by #5661

This links to the current issue, not the PR implementing this.

[AlexWaygood]

Fixed by #5661

This links to the current issue, not the PR implementing this.

Thanks, I meant #6726.