array-rank array => rank
array—an array.
rank—a non-negative integer.
Returns the number of dimensions of array.
(array-rank (make-array '())) => 0
(array-rank (make-array 4)) => 1
(array-rank (make-array '(4))) => 1
(array-rank (make-array '(2 3))) => 2
Should signal an error of type type-error if its argument is not an array.