pgsql: doc: Mention validation attempt during ALTER INDEX .. ATTACH PAR

doc: Mention validation attempt during ALTER INDEX .. ATTACH PARTITION

Since 9d3e094f12, the command tries to validate the parent index of the
named index, if invalid. The documentation did not mention this
behavior, which could be confusing.

Author: Mohamed ALi <moali.pg@gmail.com>
Discussion: /messages/by-id/CAGnOmWpHu25_LpT=zv7KtetQhqV1QEZzFYLd_TDyOLu1Od9fpw@mail.gmail.com
Backpatch-through: 14

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/0916282a0606fb788634738bab5b9f0bbde2aa08

Modified Files
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doc/src/sgml/ref/alter_index.sgml | 5 +++++
1 file changed, 5 insertions(+)