Address comments in #793

AsyncDisplayKit/ASDisplayNode.h

@@ -559,6 +559,9 @@ typedef void (^ASDisplayNodeDidLoadBlock)(ASDisplayNode *node);
  * 
  * If this node was measured, calling this method triggers an internal relayout: the calculated layout is invalidated,
  * and the supernode is notified or (if this node is the root one) a full measurement pass is executed using the old constrained size.
+ *
+ * Note: ASCellNode has special behavior in that calling this method will automatically notify 
+ * the containing ASTableView / ASCollectionView that the cell should be resized, if necessary.
  */
 - (void)setNeedsLayout;