Add a few items to analyzer's 2.19 CHANGELOG entry
Add a few items to analyzer's 2.19 CHANGELOG entry

Change-Id: I71dadebcffed30331027ad9c4ba250d3103dcc62
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/265563
Reviewed-by: Brian Wilkerson <1f7641b6b14c52b9163524ab8d9aabff80176f21@google.com>
Commit-Queue: Samuel Rawlins <5cf2cac5eec2ad6d0eb2b0f4ff6af9a590ce2bf6@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk