pgsql: Clarify docs about limitations of constraint exclusion withpart

Clarify docs about limitations of constraint exclusion with partitions

The current wording can confuse the reader about constraint exclusion
being available at query execution, but this only applies to partition
pruning.

Reported-by: Shouyu Luo
Author: David Rowley
Reviewed-by: Chapman Flack, Amit Langote
Discussion: https://postgr.es/m/15629-2ef8b22e61f8333f@postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ea05b221c2ff9d180f632ae90c806e984f15ed0d

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