There's a closed pull request on the void-packages repository

Use markdown anchors in the markdown files and update some information there
https://github.com/void-linux/void-packages/pull/21609

Description:
- Had to remove html tags from those files and use markdown anchors instead
- Changed how files in this repo are linked to each other, GH supports using `[contributing](./CONTRIBUTING.md)`.
- Added some information regarding PRs, which I took from #21481 and one of my own PRs as well. This commit can be split from the rest, but it was easier to include it, since I was already messing with the formatting.

I've tested the hyperlinks in the GH interface, and they should be good to go. The main commit for comments should be f272b49.