Fix presentation of XAML and code (dotnet#4562)

* Fix presentation of XAML and code

* Fix build and correct another XAML file

Author: mikkelbu

xml/System.Windows/Window.xml

@@ -450,12 +450,9 @@
  The following example demonstrates a <xref:System.Windows.Window> that determines whether it needs user intervention to close.  
   
  [!code-xaml[WindowClosingSnippets#WindowClosingXAML1](~/samples/snippets/csharp/VS_Snippets_Wpf/WindowClosingSnippets/CSharp/DataWindow.xaml#windowclosingxaml1)]  
-[!code-xaml[WindowClosingSnippets#WindowClosingXAML2](~/samples/snippets/csharp/VS_Snippets_Wpf/WindowClosingSnippets/CSharp/DataWindow.xaml#windowclosingxaml2)]  
   
- [!code-csharp[WindowClosingSnippets#WindowClosingCODEBEHIND1](~/samples/snippets/csharp/VS_Snippets_Wpf/WindowClosingSnippets/CSharp/DataWindow.xaml.cs#windowclosingcodebehind1)]
- [!code-vb[WindowClosingSnippets#WindowClosingCODEBEHIND1](~/samples/snippets/visualbasic/VS_Snippets_Wpf/WindowClosingSnippets/visualbasic/datawindow.xaml.vb#windowclosingcodebehind1)]  
-[!code-csharp[WindowClosingSnippets#WindowClosingCODEBEHIND2](~/samples/snippets/csharp/VS_Snippets_Wpf/WindowClosingSnippets/CSharp/DataWindow.xaml.cs#windowclosingcodebehind2)]
-[!code-vb[WindowClosingSnippets#WindowClosingCODEBEHIND2](~/samples/snippets/visualbasic/VS_Snippets_Wpf/WindowClosingSnippets/visualbasic/datawindow.xaml.vb#windowclosingcodebehind2)]  
+ [!code-csharp[WindowClosingSnippets](~/samples/snippets/csharp/VS_Snippets_Wpf/WindowClosingSnippets/CSharp/DataWindow.xaml.cs)]
+ [!code-vb[WindowClosingSnippets](~/samples/snippets/visualbasic/VS_Snippets_Wpf/WindowClosingSnippets/visualbasic/datawindow.xaml.vb)]  
   
  ]]></format>
         </remarks>