This CL adds a simple spell-checker, adds a spell-checking-phase to
messages_test to spell-check our messages, adds a new test that
spell-check our dart-code and fixes a lot of spelling mistakes / typos.
Change-Id: I8943a5bd67970e9a8a775251ae0aa97799eab097
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/112346
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Jens Johansen