docs: improve expression

Author: kenjis

docs/references/controller_filters.md

@@ -4,13 +4,15 @@
 
 !!! note
 
-    These filters are already loaded for you by the [registrar](https://codeigniter.com/user_guide/general/configuration.html#registrars) class located at **src/Config/Registrar.php**.
+    The filter `$aliases` that Shield provides are automatically added for you by the
+    [Registrar](https://codeigniter.com/user_guide/general/configuration.html#registrars)
+    class located at **src/Config/Registrar.php**. So you don't need to add in
+    your **app/Config/Filters.php**.
 
 The [Controller Filters](https://codeigniter.com/user_guide/incoming/filters.html) you can use to protect your routes Shield provides are:
 
 ```php
-public $aliases = [
-    // ...
+$aliases = [
     'session'     => \CodeIgniter\Shield\Filters\SessionAuth::class,
     'tokens'      => \CodeIgniter\Shield\Filters\TokenAuth::class,
     'hmac'        => \CodeIgniter\Shield\Filters\HmacAuth::class,