pgsql: doc PG relnotes: add links to commits

doc PG relnotes: add links to commits

Discussion: /messages/by-id/ZuYsS5XdA7hVcV9l@momjian.us

Backpatch-through: 12

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/81978404a3960ad90f6f1531af702268e7f81864

Modified Files
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doc/src/sgml/release-12.sgml | 1415 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 1415 insertions(+)