[docs] [issue42169] Apparently all documentation on @typing.overload is wrong

Change by Ken Jin <kenjin4096@gmail.com>: ---------- versions: +Python 3.6, Python 3.7 -Python 3.10, Python 3.8, Python 3.9 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue42169> _______________________________________