A11Y: Add aria markup for topic toolbars, timeline (PR #12072)

This adds some ARIA markup to some of elements on a topic page:

  • Controls under each post as a toolbar
  • The timeline as a toolbar region
  • The timeline itself as a scrollbar
  • The topic footer as a toolbar
  • The composer formatting bar as a toolbar

ARIA reference: https://www.w3.org/TR/wai-aria-practices/examples/toolbar/toolbar.html


Got some feedback from screen reader users, and the roles aren’t enough to accomplish anything… the patterns within the roles need to match as well.

@awesomerobot what should we do with this? Close for now? Merge?

Close for now, the feedback was this isn’t useful without the other pieces!