Feedback profile Rating entity should be more explicit about selection list's element type

[ViktorHaag]

Right now, the Rating entity in the Feedback profile carries the "response value" of an actor's rating in the selections list property, but the spec isn't specific about the contained elements' require type.

As with the Survey Profile's RatingScaleResponse, selections items should be strings or decimals based on the underlying Scale backing the question associated with the rating.

See also:

• Issue Survey profile Response entities should be more explicit about their contained value types #420