Enable SA1638 code fix

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1638UnitTests.cs

@@ -25,18 +25,28 @@ public async Task TestCopyrightElementWithMismatchingFileAttributeAsync()
 //   Copyright (c) FooCorp. All rights reserved.
 // </copyright>
 
+namespace Bar
+{
+}
+";
+            var fixedCode = @"// <copyright file=""Test0.cs"" company=""FooCorp"">
+// Copyright (c) FooCorp. All rights reserved.
+// </copyright>
+
 namespace Bar
 {
 }
 ";
 
             var expectedDiagnostic = this.CSharpDiagnostic(FileHeaderAnalyzers.SA1638Descriptor).WithLocation(1, 4);
             await this.VerifyCSharpDiagnosticAsync(testCode, expectedDiagnostic, CancellationToken.None).ConfigureAwait(false);
+            await this.VerifyCSharpDiagnosticAsync(fixedCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+            await this.VerifyCSharpFixAsync(testCode, fixedCode, cancellationToken: CancellationToken.None).ConfigureAwait(false);
         }
 
         protected override CodeFixProvider GetCSharpCodeFixProvider()
         {
-            throw new System.NotImplementedException();
+            return new FileHeaderCodeFixProvider();
         }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/FileHeaderCodeFixProvider.cs

@@ -36,6 +36,7 @@ internal class FileHeaderCodeFixProvider : CodeFixProvider
                 FileHeaderAnalyzers.SA1634Descriptor.Id,
                 FileHeaderAnalyzers.SA1635Descriptor.Id,
                 FileHeaderAnalyzers.SA1636Descriptor.Id,
+                FileHeaderAnalyzers.SA1638Descriptor.Id,
                 FileHeaderAnalyzers.SA1640Descriptor.Id,
                 FileHeaderAnalyzers.SA1641Descriptor.Id);