fixing a bunch of warnings from Window Walker (#2014)

* first set of warning fixes

* Since this is a Interop item, it should have a _

* Update Window.cs

* Update InteropAndHelpers.cs

looks like there was a space a the top

* Update Window.cs

src/modules/windowwalker/app/Window Walker/MainWindow.xaml.cs

@@ -117,7 +117,7 @@ namespace WindowWalker
 
         private void Window_GotFocus(object sender, RoutedEventArgs e)
         {
-            this.searchBox.Focus();
+            searchBox.Focus();
         }
     }
 }