(bug 5346) Make cats which are redirects italic in category links.

Due to bug 3311, redirects in category namespace don't work.
Furthermore they appear blue, and there is no indication anything
is wrong. This change makes the link italic to indicate to the
user that it is not a normal redirect. Only links in the
category links section of the page are affected

My only concern with this is potentially italics might not be
approrpriate in non-english languages (??). One of the main
reasons for italics is that a different colour is a larger
departure from current ui where link colours have meaning
and we already use italics for redirects on category pages,
and special:allpages.

Change-Id: I1fba042ca301844b603759c2db2cab28c3297e93
Merge "(bug 5346) Make cats which are redirects italic in category links."