[docs] [issue23702] docs.python.org/3/howto/descriptor.html still refers to "unbound methods"

Changes by Ezio Melotti <ezio.melotti@gmail.com>: ---------- versions: +Python 3.5, Python 3.6 -Python 3.4 _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue23702> _______________________________________