Draft release notes for 9.3.2.

I'm putting these up for review before I start to extract the relevant
subsets for the older branches.  It'll be easier to make any suggested
wording improvements at this stage.
Translation updates
Avoid out-of-bounds read in errfinish if error_stack_depth < 0.

If errordata_stack_depth < 0, we won't find that out and correct the
problem until CHECK_STACK_DEPTH() is invoked.  In the meantime,
elevel will be set based on an invalid read.  This is probably
harmless in practice, but it seems cleaner this way.

Xi Wang
Make NUM_TOCHAR_prepare and NUM_TOCHAR_finish macros declare "len".

Remove the variable from the enclosing scopes so that nothing can be
relying on it.  The net result of this refactoring is that we get rid
of a few unnecessary strlen() calls.

Original patch from Greg Jaskiewicz, substantially expanded by me.
Flag mmap implemenation of dynamic shared memory as resize-capable.

Error noted by Heikki Linnakangas
Increase git_changelog's timestamp_slop from 10 min to 1 day.

Many committers seem to now be using a work flow in which back-patched
commits are timestamped minutes or even hours apart in different branches
(most likely because they commit in one branch before starting work on
the next one).  git_changelog was failing to merge its reports in such
cases, so increase the max time it's willing to merge commits across.
I considered getting rid of the limit altogether, but that produces
some odd results in terms of how the merged commit gets sorted relative
to unrelated commits.
Improve draft release notes.

Per suggestions from Andres Freund.  Also fix spelling of
Sergey Burladyan's name.
doc:  update wording of ineffective SET and ABORT commands

Wording by Alvaro Herrera
Update release notes for 9.3.2, 9.2.6, 9.1.11, 9.0.15, 8.4.19.