docs($window): update example to use a module

src/ng/window.js

@@ -16,17 +16,18 @@
  * expression.
  *
  * @example
-   <example>
+   <example module="windowExample">
      <file name="index.html">
        <script>
-         function Ctrl($scope, $window) {
-           $scope.greeting = 'Hello, World!';
-           $scope.doGreeting = function(greeting) {
+         angular.module('windowExample', [])
+           .controller('ExampleController', ['$scope', '$window', function ($scope, $window) {
+             $scope.greeting = 'Hello, World!';
+             $scope.doGreeting = function(greeting) {
                $window.alert(greeting);
-           };
-         }
+             };
+           }]);
        </script>
-       <div ng-controller="Ctrl">
+       <div ng-controller="ExampleController">
          <input type="text" ng-model="greeting" />
          <button ng-click="doGreeting(greeting)">ALERT</button>
        </div>