Consistent error messages

[DimitriPapadopoulos]

The argparse error messages look like this:

usage: codespell [-h] [--version] ...
                 [files ...]
codespell: error: argument -i/--interactive: invalid choice: -1 (choose from 0, 1, 2, 3)

For codespell error messages consistent with argparse error messages:

• Use ArgumentParser.print_usage() instead of ArgumentParser.print_help().
• Print usage first and error message last.

Noticed these while finalising #3344.

[larsoner]

Thanks @DimitriPapadopoulos