Prepare notes for 3.3.0 release; updates since rc7

- Remove the rc7 suffixes to finalize this version.
- Make upgrade title case consistent with other contents.
- Update jgit information and fix recent sub-section headings.
- Add trailing core issue to the list.

Change-Id: I5d3285245408715f5337eb419be410c5d72c6c64
1 file changed