docs: better documentation for blackout window feature

docs/configuration.md

@@ -154,6 +154,10 @@ dolce:
     DOLCE_BLACKOUT_WINDOWS: 02:00-04:00,22:00-23:59
 ```
 
+If the blackout window ends, the status of all containers is compared to the last known state and notifications are sent
+if any container is in a different state than before. This enables you to schedule automatic container updates in a
+specified window and still get notified if something goes wrong during the update process.
+
 ## Run Directory
 
 If you plan on using multiple instances of Dolce (e.g. to enable multiple configurations) make sure that if this is

docs/index.md

@@ -36,7 +36,7 @@ Dolce comes with sensible defaults so you can use it out of the box but also let
 easy fashion if you so desire:
 
 <div class="grid cards single-column" markdown>
-- [:material-cog: **Configurable** via Environment Variables](./configuration.md)
+- [:material-eye-off: **Blackout Windows** so you can schedule automatic updates](./configuration.md#blackout-times)
 - [:material-database-clock: **Notification Backoff** so you don't get spammed.](./advanced/notification-backoff.md)
 - [:material-database-lock: **Graceful Error Handling** No events are lost, even if the service gets shut down](./configuration.md)
 - [:material-email-edit: **Custom Templates** for your notifications with your design](./advanced/custom-templates.md)