Board Thread:Support Requests - Getting Technical/@comment-26878768-20150827095803/@comment-4731443-20150827180429

Re: newlines in switches, I haven't had to use comments in mine to prevent them from displaying. Trying your example without the HTML comments didn't produce them either.

Regarding unused templates, I believe you can use Special:UnusedTemplates to see the list. They recommend using Special:WhatLinksHere in addition, to make sure there is no reference to the template other than template calls.