Merge pull request ember-learn#312 from ember-learn/locks-patch-2

Update index.md

Author: locks

guides/v3.5.0/controllers/index.md

@@ -96,11 +96,11 @@ We can see that if the property `isExpanded` is toggled to true, we will show th
 
 ### Common questions
 
-###### Should we use controllers in my application? I've heard they're going away!
+#### Should we use controllers in my application? I've heard they're going away!
 
 Yes! Controllers are still an integral part of an Ember application architecture, and generated by the framework even if you don't declare a Controller module explicitly.
 
-###### When should we create a Controller?
+#### When should we create a Controller?
 
 * We want to pass down actions or variables to share with a Route’s child components
 * We have a computed property that depends on the results of the model hook