pgsql: Add note about how each partition's default value is treated, in

Add note about how each partition's default value is treated, into the doc.

Column defaults may be specified separately for each partition.
But INSERT via a partitioned table ignores those partition's default values.
The former is documented, but the latter restriction not.
This commit adds the note about that restriction into the document.

Back-patch to v10 where partitioning was introduced.

Author: Fujii Masao
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/CAHGQGwEs-59omrfGF7hOHz9iMME3RbKy5ny+iftDx3LHTEn9sA@mail.gmail.com

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/80dece684f863862d68ba3cc726a4bde9d2ce568

Modified Files
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doc/src/sgml/ref/create_table.sgml | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)