docs: update PHPDoc comments

Author: kenjis

system/Filters/CSRF.php

@@ -30,14 +30,7 @@
 class CSRF implements FilterInterface
 {
     /**
-     * Do whatever processing this filter needs to do.
-     * By default it should not return anything during
-     * normal execution. However, when an abnormal state
-     * is found, it should return an instance of
-     * CodeIgniter\HTTP\Response. If it does, script
-     * execution will end and that Response will be
-     * sent back to the client, allowing for error pages,
-     * redirects, etc.
+     * CSRF verification.
      *
      * @param list<string>|null $arguments
      *

system/Security/Security.php

@@ -233,7 +233,7 @@ private function configureCookie(CookieConfig $cookie): void
     }
 
     /**
-     * CSRF Verify
+     * CSRF verification.
      *
      * @return $this
      *