in a Category page. Gives extensions the opportunity to batch load any
related data about the pages.
$type: The category type. Either 'page', 'file' or 'subcat'
-$res: Query result from DatabaseBase::select()
+$res: Query result from Wikimedia\Rdbms\IDatabase::select()
'CategoryViewer::generateLink': Before generating an output link allow
extensions opportunity to generate a more specific or relevant link.