some cleanup and documentation, see #1445

js/accessibility/KeyStateTracker.ts

@@ -274,14 +274,6 @@ class KeyStateTracker {
     return false;
   }
 
-  /**
-   * get the most recent key pressed
-   */
-  public mostRecentKeyFromList( keys: string[] ): string {
-    assert && assert( this.areKeysDown( keys ), 'Not all the keys in the list are down.' );
-    return _.minBy( keys, key => this.timeDownForKey( key ) )!;
-  }
-
   /**
    * Returns true if ALL of the keys in the list are currently down. Values of the keyList array are the
    * KeyboardEvent.code for the keys you are interested in.

js/listeners/KeyboardListener.ts

@@ -2,10 +2,10 @@
 
 /**
  * A listener for general keyboard input. Specify the keys with a `keys` option in a readable format that looks like
- * this: 'shift+t|alt+shift+r'
+ * this: [ 'shift+t', 'alt+shift+r' ]
  *
- * - '|' separates different groups of keys
- * - '+' separates each key in a single group
+ * - Each entry in the array represents a "group" of keys.
+ * - '+' separates each key in a single group.
  * - The keys leading up to the last key in the group are considered "modifier" keys. The last key in the group needs
  *   to be pressed while the modifier keys are down.
  * - The order modifier keys are pressed does not matter for firing the callback.