You are reviewing an old revision should be a warningbox

You are reviewing an old revision should be a warningbox

It's warning you about the outdated nature of the content.

Given this message can be customised and thus styled, this will
have presentation issues on certain wikis (see screenshots).

If we go ahead with this change we'll probably want to give editors
a 2 weeks heads up via tech news.

https://phabricator.wikimedia.org/F30285062
https://phabricator.wikimedia.org/F30285074
https://phabricator.wikimedia.org/F30285084

Bug: T232415
Change-Id: I7dab00d5500937c03166398d92ea65a599bf3e22