[3.6] bpo-15221: Update os.path.is*() documentation (GH-5185)#5186

Mariatta merged 1 commit intopython:3.6python/cpython:3.6from

miss-islington:backport-b3dd18d-3.6miss-islington/cpython:backport-b3dd18d-3.6Copy head branch name to clipboard