Update app/code/Magento/Theme/Model/Design/Backend/File.php

Co-Authored-By: SikailoISM <44577971+SikailoISM@users.noreply.github.com>

Author: orlangur

app/code/Magento/Theme/Model/Design/Backend/File.php

@@ -117,7 +117,7 @@ public function beforeSave()
     }
 
     /**
-     * @return File
+     * @return $this
      *
      * @throws LocalizedException
      */