Feature request: horizontal padding

[treyhunner]

I'd like to control the horizontal and vertical padding independently.

I'm using rich-cli to display some markdown nicely within a tmux window (like a slide show in a sense) and it works great for this use when I use it with --pager and specify --padding to give it a little breathing room.

My issue is that I often want 2-3 characters of padding horizontally but 0-1 characters of padding vertically.

[treyhunner]

I dug in the code a bit (though I could have found this by checking help!) and discovered that this feature is already supported.

rich file.md --pager --padding 0,3 will use 0 vertical padding and 3 horizontal.