Clarify the behavior of the system when approaching XID wraparound

When Who What
2023-10-17 14:40:11 Robert Haas (rhaas) Closed in commitfest 2023-11 with status: Committed
2023-10-17 14:40:11 Robert Haas (rhaas) Changed committer to rhaas
2023-10-02 11:26:41 Peter Eisentraut (petere) Closed in commitfest 2023-09 with status: Moved to next CF
2023-08-01 08:02:22 Daniel Gustafsson (d_gustafsson) Closed in commitfest 2023-07 with status: Moved to next CF
2023-04-09 04:15:54 Greg Stark (stark) Closed in commitfest 2023-03 with status: Moved to next CF
2023-04-09 04:15:21 Greg Stark (stark) Changed topic to Documentation
2023-04-09 01:52:11 John Naylor (john.naylor) Added john.naylor as committer
2023-04-04 16:29:28 Aleksander Alekseev (aalekseev) New status: Ready for Committer
2023-04-04 16:29:22 Aleksander Alekseev (aalekseev) Changed reviewers to John Naylor (john.naylor), Pavel Borisov (pborisov)
2023-04-03 12:34:20 Aleksander Alekseev (aalekseev) New status: Needs review
2023-03-31 07:39:52 John Naylor (john.naylor) New status: Waiting on Author
2023-03-31 07:39:43 John Naylor (john.naylor) Changed targetversion to None
2023-03-18 07:23:00 John Naylor (john.naylor) Added john.naylor as reviewer
2023-01-16 10:36:48 Aleksander Alekseev (a.alekseev) Changed authors to Aleksander Alekseev (a.alekseev)
2023-01-16 10:36:48 Aleksander Alekseev (a.alekseev) Changed targetversion to 16
2023-01-16 10:36:35 Aleksander Alekseev (a.alekseev) Attached mail thread CAJ7c6TM2D277U2wH8X78kg8pH3tdUqebV3_JCJqAkYQFHCFzeg@mail.gmail.com
2023-01-16 10:36:35 Aleksander Alekseev (a.alekseev) Created patch record