Grafana: better example for gsuite secret location

nixos/modules/monitoring/server/grafana.nix

@@ -49,7 +49,7 @@ in {
     };
     googleOAuthClientSecretFile = lib.mkOption
     { type = lib.types.path;
-      example = lib.literalExample "\${privKeyPath}/grafana-gsuite-client-secret";
+      example = lib.literalExample "/var/secret/monitoring-gsuite-client-secret";
       default = /run/keys/grafana-google-sso.secret;
       description = "The path to the GSuite SSO secret file.";
     };