UPDATE: We removed this. In the great hanging balance of features, it caused more confusion and bugs than it was useful, so we nuked it.
In any of the editors, in any language, if you put a URL into a code comment, it will be clickable.
Just a little thing we've been asked for several times so we figured we'd give it a shot. If a comment has multiple URL's it'll just use the first one.
It can be helpful. And it keeps our expectations while working on the web that we can click things to get places. The potential downside is that you can't click into the comment anymore if you need to edit it, you'll have to click outside of it and cursor in. Might be smart to have URL comments in a separate comment block than written text comments.