Restore comment detail that can only be removed after tj#1934 is merged

Author: aweebit

lib/command.js

@@ -1575,6 +1575,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
 
       // Not a recognised option by this command. Might be
       // - a subcommand,
+      // - the help option (currently not handled by this routine),
       // - an option unknown to this command,
       // - or a command-argument.