feature(calendar): add interface to set a custom year list (#5227)

docs/widgets/calendar.rst

@@ -74,6 +74,14 @@ looks like ``const char * day_names[7] = {"Su", "Mo", ...};`` Only the
 pointer of the day names is saved so the elements should be static,
 global or constant variables.
 
+Custom year list
+----------------
+
+Sets a custom year list with :cpp:expr:`lv_calendar_header_dropdown_set_year_list(calendar, years_list)`
+where ``years_list`` is a pointer to the custom years list. It can be a constant string
+like ``static const char * years = "2023\n2022\n2021\n2020\n2019";``, 
+or can be generated dynamically into a buffer as well.
+
 .. _lv_calendar_events:
 
 Events