💯 Minor codebase updates and fixes

[fregante]

I'll use this issue to add small tasks that could be done, treat it as a wishlist or a good way to start getting acquainted with the codebase.

• Find fickle selectors and change them with select(something more specific).closest(the parent);

  GitHub has been removing some feature-specific classes like .js-file-list which means that we end up with monstrosities like main > :first-child .mt-1 .btn which mean nothing and could change at any time. Ideally instead we should find the best selector inside the target element (for example its icon, select('.octicon-branch[aria-label="Create branch"]')) and then reach the desired element with .closest('.btn'):

  - select('main > :first-child .mt-1 .btn')
  + select('.octicon-branch[aria-label="Create branch"]')!.closest('.btn')

• Better yet: Replace select().closest() calls with :has #4456

[fregante]

• Add updateRepoNavigation function export to more-dropdown so that other features like releases-tab and bugs-tab can call it when they update the content. Occasionally I still see releases-tab sometimes doesn't flow into overflow hamburger menu #3347, probably due to bugs-tab

[fregante]

Let's not add any more requests to this issue. A new one can be created. We'll close this one after (almost) everything is done.

🛁 #5222

[fregante]

Closing and locking. Thanks for all the fish!