Added informal spec of "no such method forwarding".
Added informal spec of "no such method forwarding".

Change-Id: Ifa3bb120566daf0963dbb88db380fbb0e0db26c1
Reviewed-on: https://dart-review.googlesource.com/6500
Commit-Queue: Erik Ernst <251bb01623bfda2cd9151e339a6e783ca432874c@google.com>
Reviewed-by: Florian Loitsch <12d47e7a27fad71f0f62618c5962ce04e125ad18@google.com>
Reviewed-by: Leaf Petersen <9bef692239b5f624cec8e2cd5249ab1939a377aa@google.com>
Reviewed-by: Bob Nystrom <afede3a9ebedb865bee78398feff6fbe97068f17@google.com>

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