pgsql: Fix stale comments/signature after commit 28d534e2ae0a

Fix stale comments/signature after commit 28d534e2ae0a

Commit db89a47115f0 added an 'options' argument to table_tuple_update()
and table_tuple_delete(), correctly documenting it as recognizing no
values. It also (correctly) added pg_attribute_unused() to the
corresponding heap_update() argument. Commit 28d534e2ae0a then added
TABLE_UPDATE_NO_LOGICAL and TABLE_DELETE_NO_LOGICAL, but failed to
(correctly) update the comment and heap_update()'s signature.

In table_tuple_update(), move the correct explanation of 'options' to
the right place, remove the bogus one.

In table_tuple_delete(), add the missing TABLE_DELETE_NO_LOGICAL doc.

In heap_update(), remove the pg_attribute_unused() marker.

Author: Nikhil Sontakke <nikhil(at)planetscale(dot)com>
Backpatch-through: 19
Discussion: https://postgr.es/m/CA+UBoq21SzkjThYMSwSpVU-jwzpuEsf22Hq1FPbcKcDc43C29g@mail.gmail.com

Branch
------
REL_19_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/fd56954c9fe69bdc899d7cad93ec0b22b663cb30

Modified Files
--------------
src/backend/access/heap/heapam.c | 2 +-
src/include/access/tableam.h | 14 +++++++++-----
2 files changed, 10 insertions(+), 6 deletions(-)