Doc: Correct bug when deleting alarm

qrc:/AlarmDelegate.qml:139: ReferenceError: alarmModel is not defined

Change-Id: Id92b377375006e08d25a593b6532a5eaeb5b35a0
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

examples/tutorials/alarms/main.qml

@@ -64,7 +64,7 @@ ApplicationWindow {
     ListView {
         id: alarmListView
         anchors.fill: parent
-        model: AlarmModel {}
+        model: AlarmModel { id: alarmModel }
         delegate: AlarmDelegate {}
     }