Update JsConfig.cs

Author: mythz

src/ServiceStack.Text/JsConfig.cs

@@ -24,6 +24,7 @@ static JsConfig()
             JsConfig<PropertyInfo>.SerializeFn = x => x.ToString();
             JsConfig<FieldInfo>.SerializeFn = x => x.ToString();
             JsConfig<MemberInfo>.SerializeFn = x => x.ToString();
+            JsConfig<ParameterInfo>.SerializeFn = x => x.ToString();
 
             Reset();
             LicenseUtils.Init();