Improved $controller documentation to include an example for use.

Request Type: docs

How to reproduce: 

Component(s): misc core

Impact: small

Complexity: small

This issue is related to: 

**Detailed Description:**

$controller had no working examples, this is just a good look at how it can be used in other places at runtime to create controllers.

**Other Comments:**


we could check in the commit this line is from @btford