[docs] [issue39161] Py_NewInterpreter docs need updating for multi-phase initialization

Change by miss-islington <mariatta.wijaya+miss-islington@gmail.com>: ---------- pull_requests: +17329 pull_request: https://github.com/python/cpython/pull/17918 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue39161> _______________________________________