[docs] [issue15148] shutil.which() docstring could be clearer

Changes by Tshepang Lekhonkhobe <tshepang@gmail.com>: ---------- title: shutul.which() docstring could be clearer -> shutil.which() docstring could be clearer _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue15148> _______________________________________