pgsql: Doc: fix description of privileges needed for ALTER PUBLICATION.

Doc: fix description of privileges needed for ALTER PUBLICATION.

Adding a table to a publication requires ownership of the table
(in addition to ownership of the publication).  This was mentioned
nowhere.

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/a2768e44e879e62d9bb6f0bda4d695cd73d03843

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