[docs] [issue38967] Improve error message in enum for member name surrounded by underscore.

Change by Zackery Spytz <zspytz@gmail.com>: ---------- keywords: +patch pull_requests: +17746 stage: -> patch review pull_request: https://github.com/python/cpython/pull/18370 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue38967> _______________________________________