[HACKERS] Draft release notes for next week's releases are up for review

First-draft release notes are available at
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=9863017b87f3592ff663d03fc663a4f1f8fdb8b2
They should appear in a more readable form at
https://www.postgresql.org/docs/devel/static/release-9-6-2.html
after guaibasaurus' next buildfarm run, due a couple hours from now.

As usual, I've filled in the frontmost branch's section with all the
material, even though a couple of items don't apply because they only
went into further-back branches.  I'll sort that out when I split
things up.  Right now the question is whether individual items are
correctly/adequately documented.
        regards, tom lane