pgsql: docs: fix duplicate wording in PG 12 release notes

docs: fix duplicate wording in PG 12 release notes

Reported-by: nickb@imap.cc

Discussion: /messages/by-id/6b3414e1-fcef-4ad9-b123-b3ab3702d3db@www.fastmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/34d40becfa7a5c7343d0079f181597d7e06122e1

Modified Files
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doc/src/sgml/release-12.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)