Update adds more direct recommendation for authoring list items with Morphdom.

Author: kj

app/docs/md/conventions/components.md

@@ -227,7 +227,7 @@ Once added the `MorphdomMixin` will handle updating the DOM whenever an `observe
 
 ### Lists
 
-When working with lists of data in the DOM it is highly advisable to add a unique attribute to the list item like an `id` or `key`. This will assist `morphdom` in determining what items have changed in the list.
+When working with lists of data in the DOM it is highly advisable to add a unique `id` attribute to the list item. [The `state` object passed to an element's render function has a unique `instanceID` property available for this purpose]('/docs/elements/state/instance-id'). This will assist `morphdom` in determining what items have changed in the list.
 
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