bpo-38438: Simplify argparse "star nargs" usage. (GH-17106)

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 818acf4..9a1cf3a 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -449,7 +449,7 @@
    >>> parser.add_argument('--foo', type=int, default=42, help='FOO!')
    >>> parser.add_argument('bar', nargs='*', default=[1, 2, 3], help='BAR!')
    >>> parser.print_help()
-   usage: PROG [-h] [--foo FOO] [bar [bar ...]]
+   usage: PROG [-h] [--foo FOO] [bar ...]
 
    positional arguments:
     bar         BAR! (default: [1, 2, 3])