Use arguments to replace argument in argparse.rst

Author: Yzi-Li

Doc/library/argparse.rst

@@ -955,7 +955,7 @@ See also :ref:`specifying-ambiguous-arguments`. The supported values are:
 
 .. index:: single: + (plus); in argparse module
 
-* ``'+'``. Just like ``'*'``, all command-line args present are gathered into a
+* ``'+'``. Just like ``'*'``, all command-line arguments present are gathered into a
   list.  Additionally, an error message will be generated if there wasn't at
   least one command-line argument present.  For example::