Add small note.

lib/renderers/StandardRenderer.js

@@ -56,6 +56,7 @@ StandardRenderer.prototype.error = function (err) {
     // Print trace if verbose or the error has no code
     if (this._config.verbose || !err.code) {
         // TODO: In some situations, err.stack is meaningless
+        // TODO: Show stack if error is a node error
         //       Investigate why and find alternatives
         str = '\nStack trace:\n'.yellow;
         str += err.stack;