OSError stubs don't match actual types for TimeoutError subclass

OSError is currently stubbed as:

class OSError(Exception):
    errno: int
    strerror: str
    # filename, filename2 are actually str | bytes | None
    filename: Any
    filename2: Any
    if sys.platform == "win32":
        winerror: int

The CPython TimeoutError subclass of it returned by socket functions will sometimes have errno and strerror None depending on which underlying syscall detected the timeout (select() reporting 0 sockets ready vs something failing with ETIMEDOUT)

Example:

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(0.1)
try:
    # Try to connect to a host that doesn't exist on your
    # network
    s.connect(("10.10.10.10", 22))
except OSError as ex:
    print(repr(ex))
    print(f"errno is {type(ex.errno)} - {ex.errno}")
    print(f"strerror is {type(ex.strerror)} - {ex.strerror}")

produces

TimeoutError('timed out')
errno is <class 'NoneType'> - None
strerror is <class 'NoneType'> - None

on
Python 3.10.9 | packaged by conda-forge | (main, Feb 2 2023, 20:14:58) [MSC v.1929 64 bit (AMD64)]

The CPython implementation looks like it would do the same on all platforms

(@srittau 2024-09-02) Deferred until python/cpython#109601 and python/cpython#109714 are decided on.

Inspect the OSError declaration and reproduce the socket timeout example to confirm the runtime values of errno and strerror. Review python/cpython#109601 and python/cpython#109714 first; done when the stub matches the decided CPython behavior, including possible None values.