watchman: refactor transport connecting to unconfuse pytype Pytype sees `self.proc` as potentially `None` here, even though it's set by the `_connect()` logic. Instead of asserting, simply use the process returned by that method (which it sets into `self.proc` before returning, so there's no functional change here).

watchman: refactor `ctypes.windll.kernel32` references to a local variable This is flagged by pytype as an attribute-error, and it's easier to disable that in a single place.

typing: disable [unsupported-operands] warning in the largefiles outgoing hook For some reason, pytype thinks `toupload` is a set: No attribute '__setitem__' on Set[nothing] (It actually is a set in the subsequent `else` branch, but I'm not interested in trying to rewrite this to be consistent.)