pgsql: doc PG 17 relnotes: add two optimizer items

doc PG 17 relnotes: add two optimizer items

One is about subqueries becoming joins and the other is about optimizing
LIMIT by improving startup cost.

Reported-by: Andy Fan

Discussion: /messages/by-id/87h6f4ncc6.fsf@163.com

Reviewed-by: David Rowley

Backpatch-through: master

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1a48f8b40dc0fe0af67303d7e05df5f93cad36fb

Modified Files
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doc/src/sgml/release-17.sgml | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)