Revert "Drop `redundant` attribute from `a` elements"

This reverts commit c9e9bb97e2.

No longer needed due to I630410aea2852f7a72fea67bbf256b3561ea0f3f.

Change-Id: I179aa6c52da9452f39c9f816c58af44288604863

includes/TimelessTemplate.php

@@ -908,16 +908,4 @@ class TimelessTemplate extends BaseTemplate {
 
 		return $html;
 	}
-
-	/**
-	 * Extra cleanup: because we're not using SkinTemplate::buildContentActionUrls(),
-	 * some junk gets left in the tab list items unless we remove it ourselves.
-	 * (T214202)
-	 *
-	 * @inheritDoc
-	 */
-	public function makeListItem( $key, $item, $options = [] ) {
-		unset( $item['redundant'] );
-		return parent::makeListItem( $key, $item, $options );
-	}
 }