[docs-infra] Add line and word highlighting on code blocks

[danilo-leal]

Summary

Sometimes, we may want to draw attention to a specific part of a code snippet. That can be either a small function, a variable, or an entire line. We currently lack a way of doing this "natively" within our docs-infra experience. Here's just a quick preview of what this could look like:

Benchmark

• @atomiks shared his rehype-pretty-code library that we could potentially use! In terms of DX, I don't think we should deviate too much from how it is done in it.
• Docusaurus also has its own way of adding this feature that we can be inspired by too.

[JoseBarriaSantos]

Hey, can I work on this feature? Seems interesting

[danilo-leal]

@JoseBarriaSantos go ahead!