add FocusVisualStyle for some controls

src/Shared/HandyControl_Shared/Themes/Styles/ContentControl.xaml

@@ -1,5 +1,4 @@
-<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 
     <Style TargetType="ContentControl">
         <Setter Property="Focusable" Value="False"/>