docs: fix @var type

Author: kenjis

app/Config/Filters.php

@@ -15,8 +15,9 @@ class Filters extends BaseConfig
      * Configures aliases for Filter classes to
      * make reading things nicer and simpler.
      *
-     * @var array<string, string>
-     * @phpstan-var array<string, class-string>
+     * @var array<string, array<int, string>|string> [filter_name => classname]
+     *                                               or [filter_name => [classname1, classname2, ...]]
+     * @phpstan-var array<string, class-string|list<class-string>>
      */
     public array $aliases = [
         'csrf'          => CSRF::class,