typing: add type hints to the common posix/windows platform functions
These are done in sync because some platforms have empty implementations, and it
isn't obvious what the types should be without examining the other. We want the
types aligned, so @overload definitions that differ aren't generated. The only
differences here are the few methods that unconditionally raise an error are
marked as `NoReturn`, which doesn't seem to bother pytype.
A couple of the posix module functions needed to be updated with a modern
ternary operator, because pytype seems to want to use the type of the second
object in the old `return x and y` style.
copyright (c) 2006-2010 David JEAN LOUIS
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.