Improved typereader not found message

src/Discord.Net.Commands/Builders/ParameterBuilder.cs

@@ -93,7 +93,7 @@ namespace Discord.Commands.Builders
         internal ParameterInfo Build(CommandInfo info)
         {
             if (TypeReader == null)
-                throw new InvalidOperationException($"No default TypeReader found, one must be specified");
+                throw new InvalidOperationException($"No type reader found for type {ParameterType.Name}, one must be specified");
 
             return new ParameterInfo(this, info, Command.Module.Service);
         }