* Fix deadlinks take 2
Fixes the actual broken links.
```
$ yarn deadlinks
yarn run v1.22.22
$ node scripts/deadLinkChecker.js
Checking 177 markdown files...
Fetched 552 React error codes
Loaded 49 redirects from vercel.json
✓ All 1554 links are valid!
✨ Done in 0.86s.
```
* [compiler] Rewrite React Compiler Docs
We've received [feedback](https://bsky.app/profile/danabra.mov/post/3lr46ciujjs2r) that the compiler docs are difficult to understand and not prominent enough that people don't realize the compiler is a serious project and is near stable.
This PR rewrites the whole compiler doc section, giving it its own category as well as a standalone reference page.
Preview: https://react-dev-git-pr7868-fbopensource.vercel.app/
