tt tag

Hello! In a lot of messages I've found a lint error, the <tt> tag. It must be replaced with <pre>, <kbd> or <code>. here's the full list.

2 different repos are affected: MediaWiki-Extension "LookupUser" and Translating:Tracker.

For LookupUser I have submitted Gerrit:702380, pending for review now.

For Tracker hopefully User:Martin Urbanec can do something.