Use overlapped signatures of _winapi functions

[emmatyping]

For python/mypy#6148.

[srittau]

A few notes regarding the overlapped flag below.

[emmatyping]

@srittau I can provide an overload if overlapped is None but otherwise I'm not sure what you are suggesting? For example for ConnectNamedPipe the correct signature is something like:

@overload
def ConnectNamedPipe(handle: int, overlapped: Literal[True, 1]) -> Overlapped: ...
@overload
def ConnectNamedPipe(handle: int, overlapped: Optional[Literal[False, 0]] = None) -> None: ...
@overload
def ConnectNamedPipe(handle: int, overlapped: Union[bool, int, None] = None) -> Optional[Overlapped]: ...

but we aren't at the point where I can start using Literal types in typeshed, correct?

[srittau]

Um, good point. I blame too much typeshed lately. Then we should just Any as return value for now (except for the None/not provided case).

[emmatyping]

I realized I was wrong, and None is not a valid argument to overlapped, so I just did an overload of where it is omitted. Hopefully this looks like what you wanted?

[srittau]

Thank you! A good case for literal types.

[emmatyping]

Indeed! Looking forward to being able to use them :)