message: Update Locale docs where its properties are used
  Fixed: added the functions that use `weekStartsOn` and `firstWeekContainsDate` that were missing from the `Locale` documentation page
diff: *
  * @property {Object} [options] - an object with locale options.
  * @property {0|1|2|3|4|5|6} [options.weekStartsOn=0] - the index of the first day of the week (0 - Sunday).
  - * Used by `differenceInCalendarWeeks`, `endOfWeek`, `format`, `getWeek`, `getWeekOfMonth`,
  - * `getWeeksInMonth`, `isSameWeek`, `isSameWeek`, `lastDayOfWeek`, `parse`, `setDay`,
  - * `setWeek`, `startOfWeek` and `startOfWeekYear`
  + * Used by `differenceInCalendarWeeks`, `eachWeekOfInterval`, `endOfWeek`, `format`, `formatRelative`, `getWeek`, `getWeekOfMonth`,
  + * `getWeeksInMonth`, `getWeekYear`, `isMatch`, `isSameWeek`, `isThisWeek`, `lastDayOfWeek`, `parse`, `setDay`,
  + * `setWeek`, `setWeekYear`, `startOfWeek` and `startOfWeekYear`
  * @property {1|2|3|4|5|6|7} [options.firstWeekContainsDate=1] - the day of January,
  * which is always in the first week of the year.
  - * Used by `format`, `getWeek`, `getWeekYear`, `parse`, `setWeek`, `setWeekYear` and `startOfWeekYear`.
  + * Used by `format`, `getWeek`, `getWeekYear`, `isMatch`, `parse`, `setWeek`, `setWeekYear` and `startOfWeekYear`.
  *
  * @throws {RangeError} `locale` must contain `localize` property. Thrown by `format` and `formatRelative`
  * @throws {RangeError} `locale` must contain `formatLong` property. Thrown by `format` and `formatRelative`
  