pgsql: Fix function name in comment

Fix function name in comment

The name of the function resulting from the macro expansion was
incorrectly stated.

Backpatch to 16 where it was introduced.

Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: /messages/by-id/20231101.172308.1740861597185391383.horikyota.ntt@gmail.com
Backpatch-through: v16

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/0f852cccd96c6dafd7d23fb4ab073df8d370eb94

Modified Files
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src/backend/utils/adt/pgstatfuncs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)