Fix execute() access in some controllers

Backend/Controllers/APIController.php

@@ -5,7 +5,7 @@ class APIController extends Controller
 	protected array $paths = ['/api/sample'];
 	protected array $methods = ['POST'];
 
-	public function execute(): void {
+	protected function execute(): void {
 		(new APIView())->render();
 	}
 }

Backend/Controllers/NotCalledController.php

@@ -4,7 +4,7 @@ class NotCalledController extends Controller
 {
 	protected array $paths = ['/:type/:id'];
 
-	public function execute(): void {
+	protected function execute(): void {
 		$layout = new LayoutView();
 		$layout->addChild(new HeadingView("Doesn't get called when only using links from the LayoutView"));
 		$layout->addChild(new TextView("Go and work on the Router!"));

Backend/Controllers/SecondHome.php

@@ -4,7 +4,7 @@ class SecondHome extends Controller
 {
 	protected array $paths = ['/article/:id'];
 
-	public function execute(): void {
+	protected function execute(): void {
 		$layout = new LayoutView();
 		$layout->addChild(new TextView("Welcome to another route"));
 		if (($id = $this->param("id")) !== null) {