Function intersection

intersection<K extends Primitive>(a: ISet<K>, b: ISet<K>): ISet<K>
Computes the intersection of two ISet instances.

Returns a new set containing only the elements that are present in both input sets. This operation is commutative: intersection(a, b) === intersection(b, a).

Performance: O(min(n, m)) where n and m are the sizes of the input sets.
Type Parameters
- K extends Primitive
  The type of the elements.
Parameters
- a: ISet<K>
  The first set.
- b: ISet<K>
  The second set.
Returns ISet<K>
A new ISet instance containing elements common to both sets.
Example
```
const left = ISet.create<number>([1, 2, 3]);
const right = ISet.create<number>([2, 4]);

const overlap = ISet.intersection(left, right);

assert.deepStrictEqual(Array.from(overlap), [2]);
```
- Defined in src/collections/iset.mts:642