pgsql: doc: Fix typo in section "WAL configuration"

doc: Fix typo in section "WAL configuration"

pg_stat_io has an attribute named fsync_time, not sync_time.

Oversight in 2f70871c2bc1.

Discussion: /messages/by-id/Z7RkQ0EfYaqqjgz/@ip-10-97-1-34.eu-west-3.compute.internal

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f11674f8dfe811390dfeaf6f3c3a554dbeb790e1

Modified Files
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doc/src/sgml/wal.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)