support for dynamic switching languages

src/Shared/HandyControlDemo_Shared/Window/AboutWindow.xaml

@@ -6,7 +6,8 @@
            xmlns:hc="https://handyorg.github.io/handycontrol"
            mc:Ignorable="d"
            xmlns:langs="clr-namespace:HandyControlDemo.Properties.Langs"
-           Title="{x:Static langs:Lang.About}"
+           xmlns:ex="clr-namespace:HandyControlDemo.Tools.Extension"
+           Title="{ex:Lang Key={x:Static langs:LangKeys.About}}"
            ShowTitle="True"
            BorderThickness="1"
            BorderBrush="#262e2f"