feat(genapi): update faq

Author: fpagny

pages/generative-apis/faq.mdx

@@ -44,7 +44,8 @@ curl -G 'https://{data-source-id}.metrics.cockpit.fr-par.scw.cloud/prometheus/ap
 ```
 where:
 - `data-source-id` is the id of your [Scaleway Metrics data source](https://console.scaleway.com/cockpit/dataSource)
-- $COCKPIT_TOKEN is an environment variable storing your [Cockpit Token](https://console.scaleway.com/cockpit/tokens)
+- `$COCKPIT_TOKEN` is an environment variable storing your [Cockpit Token](https://console.scaleway.com/cockpit/tokens)
+- `start` and `end` time properties should be edited for your specific time range
 
 You can see your token consumption in [Scaleway Cockpit](/cockpit/). You can access it from the Scaleway console under the [Metrics tab](https://console.scaleway.com/generative-api/metrics).
 Note that: