Returns the current limit type for the rule.
It can be one of the following values:
- BCGP_RECURRENCE_RULE_LIMIT_NONE - there is no date limit
- BCGP_RECURRENCE_RULE_LIMIT_COUNT - there is a limit count (the number of recurrent appointments)
- BCGP_RECURRENCE_RULE_LIMIT_DATE - there is a limit date (recurrent appointments will be generated up to the given date.
