[AIRFLOW-5491] mark_tasks pydoc is incorrect (#6108)
[AIRFLOW-5491] mark_tasks pydoc is incorrect (#6108)

(cherry picked from commit 4f41fb1d1f097df2e98c0bd2384c81b893540fc5)

owlabs/incubator-airflow,owlabs/incubator-airflow,owlabs/incubator-airflow,owlabs/incubator-airflow