[docs] [issue17422] language reference should specify restrictions on class namespace

Change by Ananthakrishnan <ananthakrishnan15.2001@gmail.com>: ---------- pull_requests: +17939 pull_request: https://github.com/python/cpython/pull/18559 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue17422> _______________________________________