docs: public static CharMatcher inRange(final char startInclusive, final char endInclusive) {
      checkArgument(endInclusive >= startInclusive);
      return new FastMatcher() {
        @Override public boolean matches(char c) {
          return startInclusive <= c && c <= endInclusive;
        }
  
        @GwtIncompatible("java.util.BitSet")
        @Override void setBits(BitSet table) {
          table.set(startInclusive, endInclusive + 1);
        }
  
        @Override public String toString() {
          return "CharMatcher.inRange('" + showCharacter(startInclusive)
              + "', '" + showCharacter(endInclusive) + "')";
        }
      };
    }