mdx! macro support

[jareksgit]

Hello, is there any plan to support also mdx files via a macro, like the html! macro?

I found a custom implementation in this blog post (https://implfuture.dev/blog/rewriting-the-modern-web-in-rust) and since yew's own documentation is build through mdx files, it could be a nice feature.

[WorldSEnder]

This is mentioned in #2779. The consensus was that supporting mdx was the mammoth part of running the yew docs website on yew itself and was not the prior goal for now.