DAC: Unique and descriptive labels for repeatable buttons

Some kinds of buttons can occur multiple times on a single page, e.g.:

- `show` and `hide` buttons on containers on Fronts pages
- `+1` and `-1` buttons

Users who are navigating the page in a non-contextual mode will just see the same labels repeated for different instances of the buttons. It was recommended that we find a way of attaching more information to the labels for these buttons, to add context for non-contextual navigation. (E.g. `hide Opinion section`?)

(Closely related to #5335 )