[Documentation] Improve ASTableView docs. (#2316)

* Improve ASTableView docs.

* Matching ASCollectionView style.

AsyncDisplayKit/ASTableView.h

@@ -23,14 +23,14 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Asynchronous UITableView with Intelligent Preloading capabilities.
  *
- * ASTableNode is recommended over ASTableView.  This class is provided for adoption convenience.
+ * @discussion ASTableView is a true subclass of UITableView, meaning it is pointer-compatible with code that
- *
- * ASTableView is a true subclass of UITableView, meaning it is pointer-compatible with code that
  * currently uses UITableView
  *
  * The main difference is that asyncDataSource expects -nodeForRowAtIndexPath, an ASCellNode, and
  * the heightForRowAtIndexPath: method is eliminated (as are the performance problems caused by it).
  * This is made possible because ASCellNodes can calculate their own size, and preload ahead of time.
+ *
+ * @note ASTableNode is strongly recommended over ASTableView.  This class is provided for adoption convenience.
  */
 @interface ASTableView : UITableView
 
@@ -129,20 +129,29 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Triggers a relayout of all nodes.
  *
+ * @discussion This method invalidates and lays out every cell node in the table view.
  */
 - (void)relayoutItems;
 
 /**
- *  begins a batch of insert, delete reload and move operations. This method must be called from the main thread.
+ *  Begins a series of method calls that insert, delete, select, or reload rows and sections of the table view, with animation enabled and no completion block.
+ *  
+ *  @discussion You call this method to bracket a series of method calls that ends with endUpdates and that consists of operations
+ *  to insert, delete, select, and reload rows and sections of the table view. When you call endUpdates, ASTableView begins animating
+ *  the operations simultaneously. It's important to remember that the ASTableView will be processing the updates asynchronously after this call is completed.
+ *
+ *  @warning This method must be called from the main thread.
  */
 - (void)beginUpdates;
 
 /**
  *  Concludes a series of method calls that insert, delete, select, or reload rows and sections of the table view, with animation enabled and no completion block.
- *  You call this method to bracket a series of method calls that begins with beginUpdates and that consists of operations
+ *
+ *  @discussion You call this method to bracket a series of method calls that begins with beginUpdates and that consists of operations
  *  to insert, delete, select, and reload rows and sections of the table view. When you call endUpdates, ASTableView begins animating
- *  the operations simultaneously. This method is must be called from the main thread. It's important to remember that the ASTableView will
+ *  the operations simultaneously. It's important to remember that the ASTableView will be processing the updates asynchronously after this call is completed.
- *  be processing the updates asynchronously after this call is completed.
+ *
+ *  @warning This method is must be called from the main thread.
  */
 - (void)endUpdates;