code: public MonthDay atMonth(Month month) {
          return MonthDay.of(month, Math.min(day, month.maxLength()));
      }
docs: Combines this day-of-month with a month to create a {@code MonthDay}.
  <p>
  This returns a {@code MonthDay} formed from this day and the specified month.
  <p>
  This method can be used as part of a chain to produce a date:
  <pre>
  LocalDate date = day.atMonth(month).atYear(year);
  </pre>
  <p>
  If this day-of-month is invalid for the month then it will be changed
  to the last valid date for the month.
  
  @param month  the month-of-year to use, not null
  @return the year-month formed from this year and the specified month, not null