Fix typos in last newsletter.
Fix typos in last newsletter.

Address comments from https://dart-review.googlesource.com/c/sdk/+/12161

Change-Id: I05294112753891732784a38fc5ef14fb7fed291b
Reviewed-on: https://dart-review.googlesource.com/12298
Reviewed-by: Florian Loitsch <12d47e7a27fad71f0f62618c5962ce04e125ad18@google.com>

dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk