pgsql: Remove comment about historic heap vacuuming issue.

Remove comment about historic heap vacuuming issue.

Remove comment block about how heap page vacuuming used to set tuples
with storage to LP_UNUSED in a rare edge case that can no longer happen
following commit 8523492d4e.  The comments seem unnecessary now, since
it's now generally clear that heap vacuuming only applies to LP_DEAD
items from VACUUM's first heap pass following more recent work from
commits 12b5ade902 and 4f8d9d1217.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/9debd123483b970a53ba0e3de51c6234f3044df0

Modified Files
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src/backend/access/heap/vacuumlazy.c | 7 -------
1 file changed, 7 deletions(-)