Tasks: Use list label for ordering by list

apps/tasks/templates/tasks.php

@@ -2,7 +2,7 @@
 	<input type="text" id="tasks_newtask">
 	<input type="button" id="tasks_addtask" value="<?php echo $l->t('Add Task'); ?>">
 	<input type="button" id="tasks_order_due" value="<?php echo $l->t('Order Due'); ?>">
-	<input type="button" id="tasks_order_category" value="<?php echo $l->t('Order Category'); ?>">
+	<input type="button" id="tasks_order_category" value="<?php echo $l->t('Order List'); ?>">
 	<input type="button" id="tasks_order_complete" value="<?php echo $l->t('Order Complete'); ?>">
 	<input type="button" id="tasks_order_location" value="<?php echo $l->t('Order Location'); ?>">
 	<input type="button" id="tasks_order_prio" value="<?php echo $l->t('Order Priority'); ?>">