static NeighborProvider reverse(Model model) {
        return reverse(model, of(model));
    }
Returns a NeighborProvider that returns relationships that point at a
given shape rather than relationships that the given shape points at.

@param model Model to build reverse relationships from.
@return Returns the reverse neighbor provider.
smithy-model/src/main/java/software/amazon/smithy/model/neighbor/NeighborProvider.java