Remove superseded line from argparse HelpFormatter initializer

[grantjenks]

Remove superseded line from argparse HelpFormatter initializer.

[the-knights-who-say-ni]

Hello, and thanks for your contribution!

I'm a bot set up to make sure that the project can legally accept your contribution by verifying you have signed the PSF contributor agreement (CLA).

Unfortunately our records indicate you have not signed the CLA. For legal reasons we need you to sign this before we can look at your contribution. Please follow the steps outlined in the CPython devguide to rectify this issue.

You can check yourself to see if the CLA has been received.

Thanks again for your contribution, we look forward to reviewing it!

[grantjenks]

I followed the steps to complete the PSF contributor agreement (CLA).

[berkerpeksag]

Thanks!