Correct thinko in last-minute release note item.

The CREATE INDEX CONCURRENTLY bug can only be triggered by row updates,
not inserts, since the problem would arise from an update incorrectly
being made HOT.  Noted by Alvaro.

Stamp 9.6.2.

Stamp 9.5.6.

Stamp 9.4.11.

Stamp 9.3.16.

Stamp 9.6.1.

Stamp 9.5.5.

Stamp 9.4.10.

Stamp 9.3.15.

Stamp 9.2.19.