docs - slack channel renaming note (#30582) (#30589)

* slack channel renaming note

* note on alerts

Co-authored-by: Jeff Bruemmer <jeff.bruemmer@gmail.com>

docs/configuring-metabase/slack.md

@@ -71,6 +71,8 @@ On the Slack site page for your Slack app, on the left in the **Features** secti
 
 In your Slack workspace, create a public channel named whatever you want — we think something like "metabase" does just fine — then enter that channel's name in the **Slack Channel Name** field in Metabase. This channel allows your Metabase to post to your Slack workspace without having to deal with unnecessary permissions. Make sure the channel you create is the same channel that you enter in this field in Metabase (omit the "#" prefix).
 
+> If you rename the channel in Slack, you'll need to update the **Slack Channel Name** in Metabase to that new name.
+
 ## Save your changes in Metabase
 
 In Metabase, click on the **Save changes** button and that’s it! Metabase will automatically run a quick test to check that the API token and your dedicated Slack channel are working properly. If something goes wrong, it'll give you an error message.

docs/dashboards/subscriptions.md

@@ -47,6 +47,8 @@ For Slack subscriptions, you can set up a subscription for a channel (like #gene
 
 ![slack subscription options](./images/slack-subscription-options.png)
 
+> If you rename the subscribed channel in Slack, you'll need to update the subscription to point to the new Slack channel name.
+
 You can specify how often Metabase sends a Slack message (hourly, daily, weekly, or monthly), and whether to send a message if the dashboard fails to return results.
 
 ## Adding multiple subscriptions

docs/questions/sharing/alerts.md

@@ -78,10 +78,15 @@ Admins get special privileges with alerts.
 - Everyone can add any Metabase user account, email address, or even a Slack channel as a recipient of an alert that they created (but not alerts created by others).
 - Everyone can view and unsubscribe from all alerts they receive by clicking on the **gear** icon in the upper right and navigating to **Account settings** > **Notifications**.
 
+## Avoid changing the name of the alerted channel in Slack
+
+Once you set up an alert to a Slack channel, avoid changing the name of that channel in Slack. If you rename the channel in Slack, but you want Metabase to continue to send alerts to that renamed channel, you'll need to update the alert in Metabase to point to the new channel name. 
+
 ## Alert expiration
 
 Some circumstances will automatically delete alerts:
 
+- Renaming the alerted channel in Slack. Well, technically the alert won't get deleted, but Metabase will no longer have anywhere to send the alerts to. You'll need to update the alert's target channel in Metabase to the new channel's name.
 - If a saved question that has an alert gets edited in such a way that the alert doesn't make sense anymore, the alert will get deleted. For example, if a saved question with a goal line alert on it gets edited, and the goal line is removed entirely, Metabase will delete the alert.
 - If a question gets archived, Metabase will delete any alerts set up for that question.