Fix header text in 'FeatureSwitches' file

Author: Sergio0694

src/CommunityToolkit.Mvvm/Properties/FeatureSwitches.cs

@@ -1,5 +1,6 @@
-// Copyright (c) Microsoft Corporation.
-// Licensed under the MIT License.
+// 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.Runtime.CompilerServices;