First-draft release notes for 9.3.5.

First-draft release notes for 9.3.5.

As usual, the release notes for older branches will be made by cutting
these down, but put them up for community review first.

Note: a few of these items actually don't apply to 9.3, but only to older
branches.  I'll sort that out when copying the text into the older
release-X.Y.sgml files.