Gets the calendar type of the calendar system.
!(p)
The calendar type is an identifier defined by the CLDR and
!(em)Unicode Locale Data Markup Language (LDML)</em> specifications
to uniquely identify a calendar.
The {@code getCalendarType} is the concatenation of the CLDR calendar type
and the variant, if applicable, is appended separated by "-".
The calendar type is used to lookup the {@code Chronology} using {@link #of(string)}.
@return the calendar system type, null if the calendar is not defined by CLDR/LDML
@see #getId()
Gets the calendar type of the calendar system. !(p) The calendar type is an identifier defined by the CLDR and !(em)Unicode Locale Data Markup Language (LDML)</em> specifications to uniquely identify a calendar. The {@code getCalendarType} is the concatenation of the CLDR calendar type and the variant, if applicable, is appended separated by "-". The calendar type is used to lookup the {@code Chronology} using {@link #of(string)}.
@return the calendar system type, null if the calendar is not defined by CLDR/LDML @see #getId()