Unify two type_check_with_null hints for documentation purposes
Unify two type_check_with_null hints for documentation purposes

Change-Id: I6ddd19d672fc309ba07e65ed720f9eca86fee8a0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/203449
Reviewed-by: Konstantin Shcheglov <09e4d7516628963212bf4aace2f97603d2b706e4@google.com>
Commit-Queue: Brian Wilkerson <1f7641b6b14c52b9163524ab8d9aabff80176f21@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