Add items to list of functions

Add items function to the list of functions at the top of the page.

We don't need to discuss how long I was looking for a function with this functionality and didn't find it because it wasn't on the list.

Author: HoveringHalibut

articles/azure-resource-manager/templates/template-functions-object.md

@@ -13,6 +13,7 @@ Resource Manager provides several functions for working with objects in your Azu
 * [createObject](#createobject)
 * [empty](#empty)
 * [intersection](#intersection)
+* [items](#items)
 * [json](#json)
 * [length](#length)
 * [null](#null)