add ButtonGroup

replaced RadioButton with ButtonGroup

src/Shared/HandyControlDemo_Shared/Data/MessageToken.cs

@@ -98,6 +98,8 @@
 	
         public static readonly string RangeSliderDemoCtl = nameof(RangeSliderDemoCtl);
 	
+        public static readonly string ButtonGroupDemoCtl = nameof(ButtonGroupDemoCtl);
+	
         public static readonly string ButtonDemoCtl = nameof(ButtonDemoCtl);
 
         public static readonly string RepeatButtonDemoCtl = nameof(RepeatButtonDemoCtl);