Change `docs:CI/infra` label back to just `CI/infra`

[chalin]

CI/infra is for the entire repo, not just docs. While we're changing that label, review others to see if they were put in the docs bin by mistake.

If we want a prefix, it should be repo, but I'd drop the prefix.

Others to be changed since they apply to the repo/site not just the docs

• docs:accessibility --> accessibility etc
• docs:admin
• docs:mobile
• docs:ux
• docs:cleanup/refactoring isn't specific to docs
• ...

[chalin]

After some thought maybe we need site:* as a prefix too.