feat(linter): section header validation

[wdhdev]

This PR just fixes a few formatting issues (mostly just errors) in the PSL, as well as updating a couple links (mainly ones that were invalid/missing).

[simon-friedberger]

Can you replace "grandfathered" with "legacy" or something if that's what you mean here?

[wdhdev]

Done. By the way, the tests are only failing due to GitHub rate limits, there isn't anything actually wrong with the PR, it should be fine to merge. For some reason it seems the tests attempt to pull a ton of PRs, not sure why however.

[simon-friedberger]

Ah, I think that is an issue for @danderson.
I assume that, since this is a clean-up PR and it touches a lot of sections, the script is trying to get all the PRs for those sections to check the TXT records.

[wdhdev]

Are we able to merge in the meantime and create a follow up issue?

[wdhdev]

@simon-friedberger Linter has been updated to now validate section headers. I forgot the linter was actually in Python, not Go, so that made it much easier!

This PR is ready to merge unless you have any other comments. (The failing test is only due to the GitHub rate limits as I said before)

[simon-friedberger]

Damn, sorry. This is the legacy linter that we are replacing with the Go one. We don't want to update that anymore.

[wdhdev]

Ah. Should we remove this linter all together?

I'll see if I can implement the same functionality into the Go linter.

[simon-friedberger]

Yes, we should remove it. It's just here until someone puts in the work to make sure psltool covers the same things.