pgsql: Correct comments of "Fix data loss at inplace update after heap_

Correct comments of "Fix data loss at inplace update after heap_update()".

This corrects commit a07e03fd8fa7daf4d1356f7cb501ffe784ea6257.

Reported-by: Paul A Jungwirth <pj@illuminatedcomputing.com>
Reported-by: Surya Poondla <s_poondla@apple.com>
Reviewed-by: Paul A Jungwirth <pj@illuminatedcomputing.com>
Discussion: https://postgr.es/m/CA+renyWCW+_2QvXERBQ+mna6ANwAVXXmHKCA-WzL04bZRsjoBA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/0839fbe400d7807196d1442f4c781f9234ac2a4c

Modified Files
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src/backend/access/heap/heapam.c | 11 +++++++----
src/backend/access/index/genam.c |  9 +++++----
2 files changed, 12 insertions(+), 8 deletions(-)