docs: public static PermutationChromosome<Integer>
  	ofInteger(final int start, final int end) {
  		if (end <= start) {
  			throw new IllegalArgumentException(format(
  				"end <= start: %d <= %d", end, start
  			));
  		}
  
  		return ofInteger(IntRange.of(start, end), end - start);
  	}