Using variadic parameters is now handled properly by the library,
meaning the following example will run:
```php
final class SomeClass
{
/** @var string[] */
private array $values;
public function __construct(string ...$values)
{
$this->values = $values;
}
}
(new \CuyZ\Valinor\MapperBuilder())
->mapper()
->map(SomeClass::class, ['foo', 'bar', 'baz']);
```
This abstraction layer was not useful, so it is removed to simplify the
API around `ClassDefinition`.
A new method `ClassDefinition::type()` is also added, giving access to
the `ClassType` instance when working with a class definition.
