Updates intance id doc

app/docs/md/elements/state/instance-id.md

@@ -2,7 +2,7 @@
 title: Instance ID
 ---
 
-`instanceID` is a unique identifier that is generated per Custom Element instance. This enables you to differentiate between multiple instances of the same element on a page. It can also be useful when using a  string based diffing library like [Morphdom](https://github.com/patrick-steele-idem/morphdom) that require unique identifiers for DOM diffing.
+`instanceID` is a unique identifier that is generated per Custom Element instance. This enables you to differentiate between multiple instances of the same element on a page. It can also be useful when using a string based diffing library like [Morphdom](https://github.com/patrick-steele-idem/morphdom) which keys on unique identifiers to know when to update versus replace an element.
 
 ```javascript
 export default function MyCard({ html, state }) {
@@ -17,3 +17,7 @@ export default function MyCard({ html, state }) {
   `
 }
 ```
+
+<doc-callout mark="ℹ️">
+  Pro tip: As in the example above, prefix the id with the element name in order to use the id with multiple child elements.
+</doc-callout>