Fix `hint-mode`

[aadcg]

Description

Fixes #3285 Fixes #3339

Ensure that the fix doesn't re-introduce #3261.

Checklist:

• [x] Git branch state is mergable.
• [x] Changelog is up to date (via a separate commit).
• [x] New dependencies are accounted for.
• [x] Documentation is up to date.
• [x] Compilation and tests ((asdf:test-system :nyxt/gi-gtk))
  • No new compilation warnings.
  • Tests are sufficient.

[jmercouris]

I have tested it, and I don't believe it works on the URL https://developer.servicenow.com/dev.do as linked in https://github.com/atlas-engineer/nyxt/pull/3001. In other words it doesn't work ON the Shadow DOM. The same behavior is exhibited in 3.11.3. I don't know if that website https://developer.servicenow.com/dev.do has changed since the original issue was posted, but more or less none of the links work.

I confirm that the fix works for zoomed in pages. I confirm that it adds things to the shadow DOM to avoid polluting the main DOM.

[aadcg]

There are issues when using the :vi hinting-type. I'll fix those.