website/docs: improve nginx examples

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

website/docs/providers/proxy/_nginx_ingress.md

@@ -32,5 +32,5 @@ metadata:
     nginx.ingress.kubernetes.io/auth-response-headers: |
       Set-Cookie,X-authentik-username,X-authentik-groups,X-authentik-email,X-authentik-name,X-authentik-uid
     nginx.ingress.kubernetes.io/auth-snippet: |
-       proxy_set_header X-Forwarded-Host $http_host;
+       proxy_set_header Host $http_host;
 ```