feat(digests): Add more explanatory test about the min/max delivery interval (#15165)

Author: malwilley

docs/product/alerts/create-alerts/issue-alert-config.mdx

@@ -143,4 +143,6 @@ In **[Project] > Settings > Alerts**, you can configure alert email subject temp
 
 The digests feature only works for issue alert emails (not notifications sent through integrations), and unlike the [action interval](#action-interval-rate-limit), limits the total number of alert emails sent for the project. This project-level setting allows you to control the minimum and maximum delivery intervals for alerts.
 
+The minimum interval sets how soon another digest can be sent after the previous one. Each new alert resets the timer, delaying the next digest until the maximum interval is reached. If there hasn’t been a recent digest, the first alert is delivered immediately.
+
 ![A sliding adjustment scale for the frequency of alert emails.](./img/alert-digest.png)