Psalm: array_key_exists to also accept `ArrayObject`

[zerkms]

I think the stub should be like

/**
 * @psalm-template TKey as array-key
 *
 * @param TKey $key
 * @param array<TKey, mixed>|\ArrayObject<TKey, mixed> $search
 *
 * @return bool
 */
function array_key_exists($key, array $search) : bool
{
}

[muglug]

Thanks - would you mind PRing?

[zerkms]

Yep, I'll have a quick look whether any other similar functions require it as well first.