I went through the list of existing errors and tried to separate the expected errors from those that seem to be flagging unexpected issues. In particular, our effects validations are flagging patterns that our own docs examples use. I added todos for these and will follow up later.
* 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/
