feat(metadata): allow stringable objects in descriptions

[daniser]

Q	A
Branch?	main
Tickets	N/A
License	MIT
Doc PR	N/A

Allow stringable objects in descriptions of operations and resources.
The most apparent usage is for localization purposes.

Example (Laravel):

final readonly class Trans implements \Stringable
{
    public function __construct(private string $key, private array $replace = []) {}

    public function __toString(): string
    {
        return trans($this->key, $this->replace);
    }
}

Usage:

#[ApiResource(description: new Trans('resources.airport.index'))]
class Airport
{
    #[ApiProperty(description: new Trans('resources.airport.code'))]
    public string $code;
}