Fixed some templates not rendering.

src/RoutingContext.php

@@ -9,6 +9,7 @@ class RoutingContext {
     public function __construct(SeriaContext $context) {
         $this->router = new HttpRouter(errorHandler: new RoutingErrorHandler($context));
         $this->router->use('/', fn($resp) => $resp->setPoweredBy('Seria'));
+        $this->router->registerContentHandler(new StringableContentHandler); // this should really be in Index lol but i can't be bothered rn!
     }
 
     public function getRouter(): IRouter {

src/StringableContentHandler.php

@@ -0,0 +1,18 @@
+<?php
+namespace Seria;
+
+use Stringable;
+use Index\Http\HttpResponseBuilder;
+use Index\Http\Content\StringContent;
+use Index\Http\ContentHandling\IContentHandler;
+
+class StringableContentHandler implements IContentHandler {
+    public function match(mixed $content): bool {
+        return $content instanceof Stringable;
+    }
+
+    /** @param Stringable $content */
+    public function handle(HttpResponseBuilder $response, mixed $content): void {
+        $response->setContent(new StringContent((string)$content));
+    }
+}