==== Motivation
See parent {T325238} for details.
==== Proposed mockup
{F35881742}
The revealed IP address would say "show IP" before reveal occurs.
==== Testing notes
This is best tested along with {T326415}, which adds the buttons.
It should be tested locally, since it requires `$wgAutoCreateTempUser['enabled'] = true;` (only available on Beta) and the CheckUser extension (not available on Beta). It can't be fully tested on PatchDemo, because it isn't possible to edit from different IP addresses there.
Steps to test:
* Edit some article from at least one temporary account, using at least two different IP addresses for that account
* Go to the article's history page
* Clicking on the "Reveal IP" buttons should reveal the correct IP addresses for each edit. Specifically, it should reveal different IP addresses, even for the same temporary account name.