treat quarto markdown files (.qmd) as markdown files (.md)

[jgunstone]

hi there,

I love rich-cli and use it daily for viewing docs in ther terminal.
I use quarto alot which relies on quarto markdown files, they are a superset of commonmark markdown files.

if you do:

rich myquartofile.qmd

it renders it like a .txt file.

if you change the extension of the file to .md it renders it like a markdown file in the terminal and it looks loads better (despite not supporting all of the quarto's extra features).

it would be great if rich treated .qmd files like .md files by default.

thanks