message: Don't violate the 'no news are good news' principle.
  The formatter was quite noisy when it didn't have to change
  anything. Make that only happen when --verbose is chosen.
diff: @@ -104,6 +104,8 @@ ABSL_FLAG(bool, verify_convergence, true,
  "verify that re-formatting the formatted output yields "
  "no further changes, i.e. formatting is convergent.");
  +ABSL_FLAG(bool, verbose, false, "Be more verbose.");
  +
  ABSL_FLAG(int, show_largest_token_partitions, 0,
  "If > 0, print token partitioning and then "
  "exit without formatting output.");
  @@ -292,7 +294,7 @@ static bool formatOneFile(absl::string_view filename,
  FileMsg(filename) << "error writing result " << status << std::endl;
  return false;
  }
  - } else {
  + } else if (absl::GetFlag(FLAGS_verbose)) {
  FileMsg(filename) << "Already formatted, no change." << std::endl;
  }
  } else {
  