code: public String describeYear(final Map<CronFieldName, CronField> fields) {
          final String description =
                  DescriptionStrategyFactory.plainInstance(
                          resourceBundle,
                          fields.containsKey(CronFieldName.YEAR) ? fields.get(CronFieldName.YEAR).getExpression() : null
                  ).describe();
          return addExpressions(description, resourceBundle.getString("year"), resourceBundle.getString("years"));
      }
docs: Provide description for a year.
  
  @param fields - fields to describe;
  @return description - String