Remove description of commit 1944cdc98, which has now been back-patched so it's not relevant to v11 any longer. Add descriptions of other recent commits that seemed worth mentioning.
I marked the update as stopping at 2018-07-30, because it's unclear whether d06eebce5 will be allowed to stay in v11, and I didn't feel like putting effort into writing a description of it yet. If it does stay, I think it will deserve mention in the Source Code section.
7a46068f47 Update version 11 release notes.
doc/src/sgml/release-11.sgml | 113 +++++++++++++++++++++++++++++++++----------
1 file changed, 88 insertions(+), 25 deletions(-)