* b0
 * --
 *
 * The inclusive start of the range. We get the first 14 bits of this code point from the section
 * and the last 7 bits from this byte.
 *
 * The end of the range is not encoded, but can be inferred by looking at the start of the range
 * that follows.
 *
 * b1
 * --
 *
 * This is either a mapping decision or the length of the mapped output, according to this table:
 *
 * ```