[docs] [issue42061] Document __format__ method for IPv[46]Address

Change by Teugea Ioan-Teodor <teodor.teugea@gmail.com>: ---------- keywords: +patch pull_requests: +21933 stage: needs patch -> patch review pull_request: https://github.com/python/cpython/pull/23018 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue42061> _______________________________________