resolve HolidaysBase() typo for HolidayBase()
@@ -413,7 +413,7 @@ More Examples
# use the append() method which accepts a dictionary of {date: name} pairs,
# a list of dates, or even singular date/string/timestamp objects.
- >>> custom_holidays = holidays.HolidaysBase()
+ >>> custom_holidays = holidays.HolidayBase()
>>> custom_holidays.append(['2015-01-01', '07/04/2015'])
>>> custom_holidays.append(date(2015, 12, 25))
