Argshell

Fixes

* fix parser function not being called if `-h` is part of the command

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