Rich-argparse-plus

* Themes
* PDF, PNG, HTML, etc export
* Show defaults by default

FORK

Fixes
- Fix required options not coloured in the usage
* Issue 28, PR 30

Features
- A new custom usage lexer that is consistent with the formatter styles
* Issue 16, PR 17

Fixes
- Fix inconsistent coloring of args in the top usage panel
* Issue 16, PR 17
- Fix incorrect line breaks that put metavars on a alone on a new line
* Issue 12, PR 20
- Do not print help output, return it instead
* Issue 19, PR 21

Changes
- The default styles have been changed to be more in line with the new usage coloring
* PR 17
- The default `max_help_position` is now set to 24 (the default used in argparse) as line breaks
are no longer an issue
* PR 20

Removed
- The `RichHelpFormatter.renderables` property has been removed, it was never documented
* PR 20

Tests
- Run windows tests in CI
* PR 22

Fixes
- Fix compatibility with `argparse.ArgumentDefaultsHelpFormatter`
* Issue 13, PR 14

Features
- Metavars now have their own style `argparse.metavar` which defaults to `'bold cyan'`
* Issue 4, PR 9

Fixes
- Add missing ":" after the group name similar to the default HelpFormatter
* Issue 4, PR 10
- Fix padding of long options or metavars
* PR 11
- Fix overflow of text in help that was truncated
* PR 11
- Escape parameters that get substituted with % such as %(prog)s and %(default)s
* PR 11
- Fix flaky wrapping of long lines
* PR 11

Fixes
- Fix `RichHelpFormatter` does not replace `%(prog)s` in text
* Issue 5, PR 6
- Fix extra newline at the end
* Issue 7, PR 8