Update ListView.md

Author: mmsharepoint

docs/documentation/docs/controls/ListView.md

@@ -54,6 +54,10 @@ const groupByFields: IGrouping[] = [
 ];
 ```
 
+## Extend with a ContextualMenu
+
+To extend the ListView control with a [ContextualMenu](https://developer.microsoft.com/en-us/fabric#/components/contextualmenu) refer to [ListView.ContextualMenu](./ListView.ContextualMenu.md)
+
 ## Implementation
 
 The ListView control can be configured with the following properties: