Merge pull request #5012 from webandco/task/9.0-fix-fusionview-assign…

…-strict-types

TASK: Adjust types of Neos' `FusionView::assign`

Neos.Neos/Classes/View/FusionView.php

@@ -229,7 +229,7 @@ protected function getFusionRuntime(Node $currentSiteNode)
      * @param string $key
      * @param mixed $value
      */
-    public function assign($key, $value): AbstractView
+    public function assign(string $key, mixed $value): self
     {
         if ($key === 'request') {
             // the request cannot be used as "normal" fusion variable and must be treated as FusionGlobal