[docs] [issue14034] Add argparse howto

[Éric Araujo]

Éric Araujo <merwok at netwok.org> added the comment:

> You might want to coordinate with Issue 13850 a bit - they want a quick reference table before
> the first example (which would therefore mean before this howto which is replacing the first example).

The howto discussed here would be a new file in Doc/howto, so no conflict.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue14034>
_______________________________________