Simplify header after syncing with LCA

Author: Immo Landwerth

src/Microsoft.DotNet.CodeFormatting/Rules/HasCopyrightHeaderFormattingRule.cs

@@ -18,10 +18,7 @@ internal sealed class HasCopyrightHeaderFormattingRule : IFormattingRule
         static readonly string[] CopyrightHeader =
         {
             "// Copyright (c) Microsoft. All rights reserved.",
-            "// This code is licensed under the MIT License.",
-            "// THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR",
-            "// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,",
-            "// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT."
+            "// Licensed under the MIT license. See LICENSE file in the project root for full license information."
         };
 
         public async Task<Document> ProcessAsync(Document document, CancellationToken cancellationToken)