The current annotations specify the `limits` argument as an `Optional[Tuple[int, int]]`; this is incorrect. The real `resource.prlimit()` function does not accept `None` for the `limits` argument; it is only possible to avoid specifying new resource limits by omitting `limits` completely.
* resource: mark positional-only args
* resource: alias error to OSError
* resource: no longer seems incomplete
At least for Linux and Mac. Might be some things missing for FreeBSD
* resource: fix platform availability
* resource: update whitelist
