[docs] [issue42194] Docs for argparse.BooleanOptionalAction missing "New in version 3.9"

Change by Karthikeyan Singaravelan <tir.karthi@gmail.com>: ---------- nosy: +paul.j3, rhettinger _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue42194> _______________________________________