pgsql: doc: Describe better handling of indexes in ALTER TABLE ATTACH P

doc: Describe better handling of indexes in ALTER TABLE ATTACH PARTITION

When ALTER TABLE ... ATTACH PARTITION matches partition indexes to the
parent table's indexes, invalid indexes are skipped. This commit
improves the documentation to describe what e90e9275f56 has changed:
invalid indexes are skipped, and only valid indexes are considered for a
match.

Author: Mohamed Ali <moali.pg@gmail.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Discussion: /messages/by-id/CAGnOmWpAMaE-BOkpwM6mJnHcpS2QZ8yLSSaqmz+vryEsbCWWWA@mail.gmail.com
Backpatch-through: 14

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/56f2b0b5334df68b16964d4f9a0cbe9dae913227

Modified Files
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doc/src/sgml/ref/alter_table.sgml | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)