Code review comment for lp:~tblue/quam-plures/bug13_fix_credits_disp

What would be wrong with a youtube video in a template credit? Or a link or a list or an image? As long as it is properly formed and thus doesn't break the page, and as long as we're scrubbing for malicious intent I can't see why we would want to restrict. Well, other than restricting to what works inside a definition list since that is a current use of that info.