[docs] [issue40561] Add docstrings for webbrowser open functions

Change by miss-islington <mariatta.wijaya+miss-islington@gmail.com>: ---------- nosy: +miss-islington nosy_count: 4.0 -> 5.0 pull_requests: +19346 pull_request: https://github.com/python/cpython/pull/20036 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue40561> _______________________________________