Merge pull request phaserjs#3982 from spontoreau/master

Add CursorKeys type to Phaser.Input.Keyboard namespace

Author: photonstorm

src/input/keyboard/KeyboardPlugin.js

@@ -276,7 +276,8 @@ var KeyboardPlugin = new Class({
 
     /**
      * @typedef {object} CursorKeys
-     *
+     * @memberOf Phaser.Input.Keyboard
+     * 
      * @property {Phaser.Input.Keyboard.Key} [up] - A Key object mapping to the UP arrow key.
      * @property {Phaser.Input.Keyboard.Key} [down] - A Key object mapping to the DOWN arrow key.
      * @property {Phaser.Input.Keyboard.Key} [left] - A Key object mapping to the LEFT arrow key.