[TASK] Make Markdown a proper extension with DI

Author: linawolf

packages/guides-markdown/resources/config/guides-markdown.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
+
+return static function (ContainerConfigurator $container): void {
+    $container->services()
+        ->defaults()
+        ->autowire()
+        ->autoconfigure();
+};

packages/guides-markdown/src/Markdown/DependencyInjection/MarkdownExtension.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace phpDocumentor\Guides\Markdown\DependencyInjection;
+
+use Symfony\Component\Config\FileLocator;
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Extension\Extension;
+use Symfony\Component\DependencyInjection\Extension\PrependExtensionInterface;
+use Symfony\Component\DependencyInjection\Loader\PhpFileLoader;
+
+use function dirname;
+
+class MarkdownExtension extends Extension implements PrependExtensionInterface, CompilerPassInterface
+{
+    /** @param mixed[] $configs */
+    public function load(array $configs, ContainerBuilder $container): void
+    {
+        $loader = new PhpFileLoader(
+            $container,
+            new FileLocator(dirname(__DIR__, 3) . '/resources/config'),
+        );
+
+        $loader->load('guides-markdown.php');
+    }
+
+    public function prepend(ContainerBuilder $container): void
+    {
+    }
+
+    public function process(ContainerBuilder $container): void
+    {
+    }
+}