pgsql: doc: clarify which table creation is used for inheritance part.

doc:  clarify which table creation is used for inheritance part.

Previously people might assume that the partition syntax version of
CREATE TABLE is to be used for the inheritance partition table example;
mention that the non-partitioned version should be used.

Reported-by: mib@nic.at

Discussion: https://postgr.es/m/158089540905.1098.15071165437284409576@wrigleys.postgresql.org

Backpatch-through: 10

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/f116356deb75c113751db3410dec2ef59e46db73

Modified Files
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doc/src/sgml/ddl.sgml | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)