Update TV example

src/StatePattern/TVExample/TVOnState.cs

@@ -8,9 +8,16 @@ namespace StatePattern.TVExample
 {
     public class TVOnState : ITVState
     {
+        TVContext context;
+        public TVOnState(TVContext context)
+        {
+            this.context = context;
+        }
+
         public void OnPowerButtonPresed()
         {
             Console.WriteLine("TV turning off");
+            context.State = context.TvOffState;
         }
     }
 }