Link comments to page version that was current when comment was made

from Ruben Miranda on mailing list:

> Still, one thing that I think would help Confluence comments immensely, in
> addition to the separate tab - tracking the revision number of the page that
> was in effect when the comment was made. You could even add a link to that
> specific revision next to the comment header, just so you can see that
> comment in context. Others have commented on the staleness of comments
> relative to the content itself, so that might be a way to resolve any
> confusion.