[5.3] Arr::sort(): limited use of underlying Collection fixed

[Syra]

Hello,

I'm noticed that Arr::sort() that based on Collection::sortBy limiting use of $callback. In Collection it can be as closure as string in dot notation via following mechanics

protected function valueRetriever($value)
{
    if ($this->useAsCallable($value)) {
        return $value;
    }

    return function ($item) use ($value) {
        return data_get($item, $value);
    };
}

Checkout please.

Thanks,
Alex