Complète la traduction de library/argparse (#88)

Closes #66

Co-authored-by: Mathias Laurin <Mathias.Laurin+github.com@gmail.com>
Reviewed-on: https://git.afpy.org/AFPy/python-docs-fr/pulls/88
Co-authored-by: Synss <mathias.laurin+afpy.org@gmail.com>
Co-committed-by: Synss <mathias.laurin+afpy.org@gmail.com>

Author: 2 people