Add description about using geqo to EXPLAIN or debug log.

When Who What
2022-10-12 06:04:39 Michael Paquier (michael-kun) Closed in commitfest 2022-09 with status: Returned with feedback
2022-08-01 22:18:27 Jacob Champion (jchampion) New status: Waiting on Author
2022-08-01 22:18:23 Jacob Champion (jchampion) Closed in commitfest 2022-07 with status: Moved to next CF
2022-06-24 07:24:50 Peter Eisentraut (petere) Changed authors to masaya kawamoto (kawamoto)
2022-06-13 01:02:55 masaya kawamoto (kawamoto) Attached mail thread 20220510100548.93be160a9fa88a11f0835c23@sraoss.co.jp
2022-06-13 01:02:55 masaya kawamoto (kawamoto) Created patch record