[docs] [issue12028] threading._get_ident(): remove it in the doc and make it public

Antoine Pitrou <pitrou@free.fr> added the comment:

I think that threading._get_ident() is more reliable than threading.current_thread().ident because Thread.ident can be None in some cases.

In which case can it be None? ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue12028> _______________________________________