update headers (again)

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/RichSuggestBox/RichSuggestBoxPage.xaml.cs

@@ -1,4 +1,8 @@
-using System;
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.Toolkit.Uwp.UI.Controls;

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/RichSuggestBox/SuggestionTemplateSelector.cs

@@ -1,4 +1,8 @@
-using Windows.UI.Xaml;
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 
 namespace Microsoft.Toolkit.Uwp.SampleApp.SamplePages