Add link to Authentik Integrations Documentation (#5828)

docs/en/admins/16_OpenID-Connect-Authentik.md

@@ -2,6 +2,8 @@
 
 **[authentik](https://goauthentik.io/)** is an open-source Identity Provider compatible with OpenID Connect (OIDC) (see [FreshRSS’ OpenID Connect documentation](16_OpenID-Connect.md)).
 
+You can find more information in [authentik integrations documentation](https://goauthentik.io/integrations/services/freshrss/).
+
 ## 1. Create OAuth2/OpenID Provider
 
 In authentik Web interface:

docs/en/admins/16_OpenID-Connect.md

@@ -44,4 +44,4 @@ After install, the method can be changed in *Administration > Authentication*. N
 
 See specific instructions for:
 
-* [authentik](16_OpenID-Connect-Authentik.md)
+* Authentik : [here](16_OpenID-Connect-Authentik.md) or [here](https://goauthentik.io/integrations/services/freshrss/)