Expose property return value where appropriate

From slack:

Hi all, Is there a way to see the data that is returned from a function that I call `stest/check` on? For example, I can see all the data generated for that function's inputs by passing in a `reporter-fn` to the `opts` but I can't seem to find a way to access that data for the returns. I'd love to pass a function in to format the output data as needed. thx for any pointers!