Update Grid.js

Fixes scope declaration in documentation.

src/js/core/factories/Grid.js

@@ -378,7 +378,7 @@ angular.module('ui.grid')
      * getColumnSorting, which is an array of gridColumns
      * that have sorting on them, sorted in priority order.
      *
-     * @param {$scope} The scope of the controller. This is used to deregister this event when the scope is destroyed.
+     * @param {$scope} scope The scope of the controller. This is used to deregister this event when the scope is destroyed.
      * @param {Function} callBack Will be called when the event is emited. The function passes back an array of columns with
      * sorts on them, in priority order.
      *
@@ -398,7 +398,7 @@ angular.module('ui.grid')
      * @description The visibility of a column has changed,
      * the column itself is passed out as a parameter of the event.
      * 
-     * @param {$scope} The scope of the controller. This is used to deregister this event when the scope is destroyed.
+     * @param {$scope} scope The scope of the controller. This is used to deregister this event when the scope is destroyed.
      * @param {Function} callBack Will be called when the event is emited. The function passes back the GridCol that has changed.
      *
      * @example