pgsql: Update obsolete nbtree array preprocessing comments.

Update obsolete nbtree array preprocessing comments.

The array->scan_key references fixed up at the end of preprocessing
start out as offsets into the arrayKeyData[] array (the array returned
by _bt_preprocess_array_keys at the start of preprocessing that involves
array scan keys). Offsets into the arrayKeyData[] array are no longer
guaranteed to be valid offsets into our original scan->keyData[] input
scan key array, but comments describing the array->scan_key references
still talked about scan->keyData[]. Update those comments.

Oversight in commit b5249741.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3da436ec09ae2f1a0167d4b74b30449f0292f581

Modified Files
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src/backend/access/nbtree/nbtutils.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)