code: public static CharRanges expandToAllMatched(CharRanges ranges) {
      CharRanges caseSensitive = ranges.intersection(CASE_SENSITIVE);
      if (caseSensitive.isEmpty()) { return ranges; }
      CharRanges expanded = CharRanges.EMPTY;
      for (DeltaSet ds : DELTA_SETS) {
        expanded = expanded.union(
            caseSensitive.intersection(ds.codeUnits).shift(-ds.delta));
      }
      return ranges.union(expanded);
    }
docs: Given a character range that may include case sensitive code-units,
  such as {@code [0-9B-M]}, returns the character range that includes all
  the code-units in the input and those that are case-insensitively
  equivalent to a code-unit in the input.