Update doc/security/rack-attack.md

doc/security/rack_attack.md

@@ -10,8 +10,7 @@ Rack Attack offers IP whitelisting, blacklisting, Fail2ban style filtering and
 tracking.
 
 **Note:** Starting with 11.2, Rack Attack is disabled by default. To continue
-using this feature, please enable it in your `gitlab.rb` by setting
-`gitlab_rails['rack_attack_git_basic_auth'] = true`.
+using this feature, please enable it by [configuring `gitlab.rb` as described in Settings](#settings).
 
 By default, user sign-in, user sign-up (if enabled), and user password reset is
 limited to 6 requests per minute. After trying for 6 times, the client will