Support default content in the default slot

[ewingd]

Tempest version

1.0.0-beta.1

PHP version

8.4

Operating system

Linux

Description

When a default value is set for a x-slot tag, the default value is always used.

Steps to reproduce

<?php
// app/Test/TestController.php

declare(strict_types=1);

namespace App\Test;

use Tempest\Router\Get;
use Tempest\View\View;

use function Tempest\view;

class TestController
{
    #[Get("/test")]
    public function __invoke(): View
    {
        return view('test.view.php');
    }
}

<!-- test.view.php -->
<x-link/><br/>
<x-link>Custom Value</x-link>

<!-- x-link.view.php -->

<a>
    <x-slot>Default Value</x-slot>
</a>

Expected Output:

Default Value
Custom Value

Actual Output:

Default Value
Default Value