Fix PHPStan errors

src/Concerns/RegistersCurrencies.php

@@ -128,7 +128,10 @@ trait RegistersCurrencies
         }
 
         if (class_exists($currency) && (new ReflectionClass($currency))->isSubclassOf(Currency::class)) {
-            return (new $currency)->code();
+            /** @var Currency $currency * */
+            $currency = new $currency;
+
+            return $currency->code();
         }
 
         throw new InvalidCurrencyException(

src/Currency.php

@@ -8,6 +8,7 @@ use ArchTech\Money\Exceptions\InvalidCurrencyException;
 use Illuminate\Contracts\Support\Arrayable;
 use JsonSerializable;
 
+/** @implements Arrayable<string, string|int|float> */
 class Currency implements Arrayable, JsonSerializable
 {
     /** Code of the currency (e.g. 'CZK'). */

src/Money.php

@@ -8,6 +8,7 @@ use Illuminate\Contracts\Support\Arrayable;
 use JsonSerializable;
 use Livewire\Wireable;
 
+/** @implements Arrayable<string, string|int> */
 final class Money implements JsonSerializable, Arrayable, Wireable
 {
     protected int $value;