docs: add @var for psalm errors

Author: kenjis

system/Config/Services.php

@@ -331,6 +331,7 @@ public static function image(?string $handler = null, ?Images $config = null, bo
             return static::getSharedInstance('image', $handler, $config);
         }
 
+        /** @var Images $config */
         $config ??= config('Images');
         $handler = $handler ?: $config->defaultHandler;
         $class   = $config->handlers[$handler];
@@ -638,6 +639,7 @@ public static function session(?App $config = null, bool $getShared = true)
             return static::getSharedInstance('session', $config);
         }
 
+        /** @var App $config */
         $config ??= config('App');
         $logger = AppServices::logger();