docs(tutorial/step-12): correct file path

Fixed wrong file path:
- angular/angular-animate.js -> angular-animate/angular-animate.js, which meets the code in app/index.html

Closes angular#7168

Author: aminRX

docs/content/tutorial/step_12.ngdoc

@@ -92,7 +92,7 @@ __`app/index.html`.__
   ...
 
   <!-- required module to enable animation support in AngularJS -->
-  <script src="../bower_components/angular/angular-animate.js"></script>
+  <script src="../bower_components/angular-animate/angular-animate.js"></script>
 
   <!-- for JavaScript Animations -->
   <script src="js/animations.js"></script>