Borderless code blocks in Markdown rendering

[calexicoz]

Hi there,

This is a follow up to Textualize/rich-cli#27. I'll give a brief description of my use case to explain.

I have a simple alias called tl which essentially does rich TLDR.md. In various projects, I have a TLDR.md file that will give you quick instructions for common things (installing, running, testing, etc). I have many projects with many different ... ways. This allows me to jump from place to place, just type tl and get the commands I need to do what I need to do in this particular project without having to memorize all those discrepancies. I picked Rich to display those, as the output is really nice in the terminal, and a pleasure to read.

At the moment, the code blocks have a lined bounded box. This means that I cannot directly copy/paste the content of said code/blocks because this will copy the line on the left side. Code blocks have a background already, so they are highlighted compared to the rest of the text. Having no line around the block though would allow simple copy/pasting of content, which I would assume is something common to do with code blocks.

With all that said, changing such a default is likely to break many users, so I'm unsure whether that's something that can be done or desirable. If it's not, I'll maybe investigate how to write a custom CLI using Rich that does this.

Happy to hear thoughts on this.

Thanks!