Docs pre-check never works because of 429 errors

[feywind]

GitHub changed their quota limits for loading files by non-logged-in bots, and now linkinator basically never works. Most of our other repos have stopped running it as a PR pre-check, so I want to do the same here and make the red/green work, as well as automerge.

Edit: We just need to update linkinator at some point when versions are compatible.

[feywind]

Related: #2114

[feywind]

Since the CI will be moving around anyway (monorepo), I'm going to close this. There's been no movement on it, and we'll no doubt be doing this across packages later on.