Issue
As a user, I want to navigate through revisions without always scrolling to the top of the page.

Background
Currently the only way to slide to another revision is to scroll to the top of the page and click one of the buttons / knobs. This is a particularly cumbersome when navigating a very long page with few changes in the same area (e.g. middle of a page). Also, with the new VisualEditor/Diffs it is possible to see most of the context without scrolling back up.

Possible solutions

• Make the revision slider toolbar sticky as the user scrolls; or
• Make a simpler smaller toolbar that follows the user while scrolling, and contains back and forth buttons (maybe at the bottom of the page).

Using keyboard shortcuts to navigate revisions (using a userscripts) made it clear that this is useful.

Copied over from feedback on https://www.mediawiki.org/wiki/Topic:Ttqh7as4cz2b6kng