Make -h act like --help as per docs (#299)

Closes #298

Co-authored-by: Doyle Rowland <doyle.rowland@reliaqual.com>

Author: peterjc

src/docformatter/__main__.py

@@ -113,7 +113,7 @@ def _main(argv, standard_out, standard_error, standard_in):
     """Run internal main entry point."""
     configurator = _configuration.Configurater(argv)
 
-    if "--help" in configurator.args_lst:
+    if "--help" in configurator.args_lst or "-h" in configurator.args_lst:
         _help()
         return 0
     else: