Set the highest index in the array to the given number, equivalent to
Perl's C<$#array = $fill;>.
-The number of elements in the an array will be C<fill + 1> after
+The number of elements in the array will be C<fill + 1> after
av_fill() returns. If the array was previously shorter, then the
additional elements appended are set to NULL. If the array
was longer, then the excess elements are freed. C<av_fill(av, -1)> is