Argshell

Fixes

* fix shell_docs parser description formatting

Performance improvements

* when passing a parser to `with_parser`, the `prog` attribute will be set to the name of the decorated function
Docs

* increase font size of svgs

Others

* add 'assets' to sdist excludes

New Features

* implement command documentation generation
Fixes

* prevent missing required args message when using `-h/--help`
Refactorings

* change `ArgshellParser` inheritance
Docs

* rewrite readme

Refactorings

* use gradient when displaying command list

New Features

* implement `rich` based help formatter
Others

* move type ignore comment after formatting goofed it up