code: protected final LocalDate plusYearsAdjustToBegin(final LocalDate date,
              final int years) {
          final LocalDate adjustedYears = plusYears(date, years);
          final LocalDate firstMonth = firstMonth(adjustedYears);
          return firstDayOfMonth(firstMonth);
      }
docs: Add years to the date and then adjust to the beginning of the resultant
  year.
  
  @param date input date
  @param years years to add
  @return new date