Headings for staff catalog record views

I have added the subheadings, along with the necessary CSS to avoid major visual changes to font size, weight, line height, and whitespace.

Branch here:
https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/sleary/LP2039483-staffcat-subheadings

To test, you can either use a screen reader's page navigation tools or a browser extension that simulates the landmarks and headings list; I use SkipTo Landmarks and Navigation (screenshot attached).

Previously, only 1) Staff Catalog appeared in the headings list. It is now:

1) Staff Catalog
  2) Record Summary
    3) Staff View
    3) Item Table
    3) MARC Edit
    3) MARC View
    3) Record Notes
    3) View Holds
    3) Monograph Parts
    3) Holdings View
    3) Conjoined Items
    3) Shelf Browse
      4) FIC 220 @ BR4
      4) FIC 220 @ BM1
      4) [etc.]

Does it make sense to user a lower heading level for everything after Record Summary, or should I move Staff View, etc. up to the same level?

Based on feedback at today's code review session, I'm going to make the tabs H2s and add a landmark for the search form.

Headings revised! The search form already had a landmark, which I had overlooked.

The heading structure is now:

1) Staff Catalog
  2) Record Summary
  2) Staff View
  2) Item Table
  2) MARC Edit
  2) (etc.)

Adding my signoff to this ticket with my name, rfrasur, and email, <email address hidden>.

I've just updated this branch to accommodate the new Added Content tab (bug 1991294).

Removing signoff since there is a new update still to be tested.

This will require someone to verify locally who has Novelist added content.

It can be tested looking at all the other tabs; the NoveList tab just needed to be made consistent to avoid merge conflicts.

Thanks Stephanie and Ruth! Fix merged to main.