Language agnostic literate markdown tangler

[stefanocoretta]

Description

Hello! I think it would be great if Quarto could natively reproduce the behaviour of the literate markdown tangler (https://github.com/driusan/lmt/tree/master, written in Go).

This feature would allow Knuth's version of literate programming, in which a programme/script can be tangled from a documentation file. Code chunks can be named and references included in other code chunks. The tangler would create scripts/files based on the code in the documentation (possibly, multiple output files for a single source file).

[stefanocoretta]

Actually, I realised a pandoc lua filter would do it, so I started working on one: https://github.com/stefanocoretta/lmt

It works. I just need to change it so that indentation in the referenced blocks is kept, as the Go lmt does.