my Argparse tutorial now part of official Python documentation

I am very glad that a tutorial I started writing over 2 months ago has finally been added to the howto section of CPython documentation. It took a lot of iteration (over 7) in total before finally being accepted. But even then, it's still not fully satisfactory for me, and I really hope that someone else with fresh eyes is going to go through all of it and offer improvements. Even better, I hope people will find it useful. I know I would have when I started doing argument parsing. I found the main module documention overwhelming, and the very first example is in fact why I even started writing this tutorial at all, as is evident on the relevant issue.