typing: add trivial type hints to rest of the windows platform module Skipping the file wrappers for now because there's interplay with C code, and making them subclass `typing.BinaryIO_Proxy` confuses PyCharm a bit.

typing: add type hints to the rest of the posix module These methods either don't have an analog in the windows module, or are aliased in the windows module from something else (like os.path.xxx).

typing: add type hints to the platform `cachestat` classes