CLI docs: remove hack for wrapping the CLI reference

[stefmolin]

Maybe this was a limitation of the theme at the time, but try to switch from the hack here:

https://github.com/stefmolin/data-morph/blob/f9af20101aeb5e1971c3ff5ecf731dcff43dee4b/src/data_morph/cli.py#L212-L230

to use generate_parser directly in the docs (here).

Try updating the version of the theme and/or adding some CSS.