Creates a comment with the specified comment string, start position and length.
<void> CommentCollection.addAtPosition(<string> comment, <number> start, <number> length, [<AddCommentCallback> callback], [<ErrorCallback> errorCallback])
|comment||The comment string.|
|start||The index (one-based) of the first character which belongs to the comment.|
|length||The number of characters which belong to the comment.|
|callback||Optional. Receives the result of the add operation.|
||Optional. Is called when the operation failed with an error.|