docs: private static String keyToGoWithElementsString(String label, DuplicateGroupedAndTyped elements) {
      /*
       * elements.toString(), which the caller is going to use, includes the homogeneous type (if
       * any), so we don't want to include it here. (And it's better to have it in the value, rather
       * than in the key, so that it doesn't push the horizontally aligned values over too far.)
       */
      return lenientFormat("%s (%s)", label, elements.totalCopies());
    }