Add issue reference

Author: GrahamTheCoder

ICSharpCode.CodeConverter/Shared/ProjectConversion.cs

@@ -170,6 +170,7 @@ private static async Task<IEnumerable<ConversionResult>> ConvertProjectContents(
 
         /// <summary>
         /// Use this to stop the library exiting the process without telling us.
+        /// https://github.com/dotnet/roslyn/issues/41724
         /// </summary>
         /// <remarks>
         /// The simplification code in particular is quite buggy, scattered with "throw ExceptionUtilities.Unreachable" with no particular reasoning for why the code wouldn't be reachable.