When sampling, `row-fn` called with entire sample, and not `row`

[atgreen]

read-csv-sample contains:

  (iter
    (for row in-csv stream-or-string skipping-header skip-first-p)
    (sampling row into sample size sample-size)
    (finally
     (return
       (iter (for row in sample)
         (when map-fn (setf row (funcall map-fn row)))
         (when row-fn (funcall row-fn sample))
         (collect row))))))

That second last line should be (when row-fn (funcall row-fn row)).