docs(tutorial/step_12): added 'see phone-detail change'

This one caught me out for a while because, despite the note underneath, I didn't notice the addition
of <div class="phone-images"> and it's repeater until later.

Closes #9924

Author: danielmbarlow

docs/content/tutorial/step_12.ngdoc

@@ -369,7 +369,8 @@ occur whenever the CSS class itself changes.
 Whenever a new phone thumbnail is selected, the state changes and the `.active` CSS class is added
 to the matching profile image and the animation plays.
 
-Let's get started and tweak our HTML code on the `phone-detail.html` page first:
+Let's get started and tweak our HTML code on the `phone-detail.html` page first. Notice that we 
+have changed the way we display our large image:
 
 __`app/partials/phone-detail.html`.__