If a redirect is categorized, it is marked in the category listing as
class=stub, e.g. (from de:)
<a href="/wiki/Petra_Schaaf" class="stub" title="">Petra Schaaf</a>
in special:Allpages redirects are already marked as separate
class="allpagesredirect" - an equivalent classification in categories would be
very useful, since a classification as stub is surely wrong and misleading if
mark short articles is activated.