Fix variable name

Author: antonsamson-msft

articles/communication-services/quickstarts/rooms/includes/rooms-quickstart-net.md

@@ -56,7 +56,7 @@ Create a new `RoomsClient` object that will be used to create new `rooms` and ma
 ```csharp
 // Find your Communication Services resource in the Azure portal
 var connectionString = "<connection_string>";
-RoomsClient roomsCollection = new RoomsClient(connectionString);
+RoomsClient roomsClient = new RoomsClient(connectionString);
 ```
 
 ### Create a room