Using failover slots for PG-non_PG logical replication

Hi All,

The failover slots documentation [1] is good for PG - PG logical
replication, but the first two queries require pg_subscription which
may not be present in non-PG downstream. Somebody looking to setup
failover slots for non-PG subscriber may not find the page useful.
However, the third query, when modified to mention the replication
slots relevant to the downstream is useful to them. How to find the
replication slots to be synchronized is a problem specific to the type
of downstream. Such a setup should add those slots to
sync_replication_slots. I think the chapter should mention that the
3rd query should also include the slots mentioned in
sync_replication_slots for PG-non_PG logical replication setup.

[1] https://www.postgresql.org/docs/current/logical-replication-failover.html

--
Best Wishes,
Ashutosh Bapat