[docs] [issue13402] Document absoluteness of sys.executable

Eryk Sun added the comment: "/opt/local/bin/../bin/python2.7" is an absolute path. >>> os.path.isabs('/opt/local/bin/../bin/python2.7') True It's not relative to the working directory. ---------- nosy: +eryksun _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue13402> _______________________________________