docs(ngController): Fix priority value mentioned in the docs

src/ng/directive/ngController.js

@@ -23,6 +23,7 @@
  *
  * @element ANY
  * @scope
+ * @priority 500
  * @param {expression} ngController Name of a constructor function registered with the current
  * {@link ng.$controllerProvider $controllerProvider} or an {@link guide/expression expression}
  * that on the current scope evaluates to a constructor function.