[wp-forums] Move the "RSS feed for this topic" link to infobox

[Jeremy Visser]

The "RSS feed for this topic" link at the end of forum topics (located
just above the Reply section) is very lonely over there.

Can I suggest moving it into the infobox, along with the links like
"This topic is one of your favorites [x]"?

(No, actually, I won't ask to suggest it. I'll go ahead and suggest it
regardless.)