Move 'compare' tab on revisions from bottom to top of page

[ElizabethPace]

Often when comparing revisions on content pages, it's newer revisions a user wants to compare. The compare button is at the bottom of the page and a lot of scrolling's involved if it's a page with a lot of revisions.

Consider moving the compare button to the top of the page to make the comparing revisions easier.

[hsorby]

Thanks, I am working on the release process and haven't gotten to the part where we update the website yet.