Wishlist: support tabs or code groups

[giordano]

Sphinx, vitepress and other tools are able to group multiple blocks of code in a single panel and you use tabs to switch between the different "versions" of the code. It'd be cool to be able to do the same in Documenter.jl.

[mortenpi]

This is a good idea, but I think it should be done as an extension package in the first instance.

One big thing we're missing is the Markdown syntax for this.

[goerz]

Maybe what we’d want for this is a quarto reader (which is the markdown format I most associate with that feature)