Fix typo

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/AnalyzerInfo.cs

@@ -2,7 +2,7 @@
 // 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;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;