Add unit test for Response Handlebars

src/WireMock/RequestBuilders/Request.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using JetBrains.Annotations;
 using WireMock.Matchers;
 using WireMock.Matchers.Request;
 
@@ -308,4 +307,4 @@ namespace WireMock.RequestBuilders
             return this;
         }
     }
-}
+}