Update 05-loops-conditions-existing.md (Azure#2102)

* Update 05-loops-conditions-existing.md

Clarifying that we do indeed support for loops with index. An example may be good because in some languages like python the index comes before the item.

* Address feedback

* url path

* Update 05-loops-conditions-existing.md

docs/tutorial/05-loops-conditions-existing.md

@@ -70,7 +70,7 @@ resource foo 'my.provider/type@2021-03-01' = [for <ITERATOR_NAME> in <ARRAY> = {
 
 `ITERATOR_NAME` is a new symbol that is only available inside the body of the resource declaration. It can be any name you would like and represents the current item in the array.
 
-Let's remove our condition and replace it with a loop based on an input of container names:
+Let's remove our condition and replace it with a loop based on an input of container names: 
 
 ```bicep
 param containerNames array = [
@@ -85,6 +85,13 @@ resource blob 'Microsoft.Storage/storageAccounts/blobServices/containers@2019-06
 }]
 ```
 
+There's also a [loop index variant](../spec/loops.md#use-the-loop-index) which gives us access to the current item's index in the array:
+```
+resource blob 'Microsoft.Storage/storageAccounts/blobServices/containers@2019-06-01' = [for (name, index) in containerNames: {
+  name: '${stg.name}/default/${name}-${index + 1}'
+}]
+```
+
 This change also implicitly changes the type of the `resource` into an array of resources (will show up as `resources[]` on hover), rather than a single resource. In order to access one of the resources, I use array access syntax just like I do for any array in Bicep. Let's add an output that emits the id of each blob container.
 
 ```bicep