Minimally update ReleaseNotes.html for 2.8 development; uncomment and
update the big red warning at the top. Most of the old content remains
and awaits revision.

Clear out the API changes section, and start it up again with a
mention of the add->fadd transition.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102977 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed