Обсуждение: pgsql: doc: update PG 12 release notes, v2

doc:  update PG 12 release notes, v2

Adjustments requested by reviewers.

Reported-by: Amit Kapila, Thomas Munro, Andrew Gierth, Amit Langote, Oleg Bartunov, Michael Paquier, Alvaro Herrera,
TatsuoIshii 

Discussion: https://postgr.es/m/20190506233029.ozwged67i7s4qd6c@momjian.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/64084d6857b1d8ac05ae46f658b6c244aa6ab591

Modified Files
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doc/src/sgml/release-12.sgml | 81 ++++++++++++++++++++------------------------
1 file changed, 36 insertions(+), 45 deletions(-)