Remove 'legacy' definition for CronDataIntervalTimetable (#39780)

airflow/config_templates/config.yml

@@ -2495,17 +2495,16 @@ scheduler:
     create_cron_data_intervals:
       description: |
         Whether to create DAG runs that span an interval or one single point in time for cron schedules, when
-        a cron string is provided to `schedule` argument of a DAG. If True,
-        CronDataIntervalTimetable is used, which is the legacy Airflow behavior suitable
-        for DAGs with well-defined data_interval you get contiguous intervals from the end of the previous
-        interval up to the scheduled datetime. If False, CronTriggerTimetable is used,
-        which is closer to the behavior of cron itself.
+        a cron string is provided to ``schedule`` argument of a DAG.
 
-        Notably, for CronTriggerTimetable, the logical_date is the same as the time the DAG Run will try to
-        schedule, while for CronDataIntervalTimetable, the logical_date is the beginning of the data interval,
-        but the DAG Run will try to schedule at the end of the data interval. For more differences
-        between the two Timetables, see
-        https://airflow.apache.org/docs/apache-airflow/stable/authoring-and-scheduling/timetable.html#differences-between-the-two-cron-timetables
+        * ``True``: **CronDataIntervalTimetable** is used, which is suitable
+          for DAGs with well-defined data interval. You get contiguous intervals from the end of the previous
+          interval up to the scheduled datetime.
+        * ``False``: **CronTriggerTimetable** is used, which is closer to the behavior of cron itself.
+
+        Notably, for **CronTriggerTimetable**, the logical date is the same as the time the DAG Run will
+        try to schedule, while for **CronDataIntervalTimetable**, the logical date is the beginning of
+        the data interval, but the DAG Run will try to schedule at the end of the data interval.
       version_added: 2.9.0
       type: boolean
       example: ~