Returns true if a util/set/hashset contains the specified element.
Since: 3.0
Parameters
set: The original set.elem: The element to be checked.eq: A equality function. If it's ignored, use==to compare elements.hash: A hash function. If it's ignored, convert each element to a string and hash it.
Examples
use <util/set/hashset.scad>
use <util/set/hashset_has.scad>
s = hashset([1, 2, 3, 4, 5]);
assert(hashset_has(s, 3));

