doc: markup for PG 11 release notes and included email tips
Branch------master
Details-------https://git.postgresql.org/pg/commitdiff/6186d0bd615ed2eb921ad13ccdf4ceed19d3f7a8
Modified Files--------------doc/src/sgml/release-11.sgml | 950 +++++++++++++++++++++++++------------------1 file changed, 554 insertions(+), 396 deletions(-)
