Docs: Update email notifier documentation (#22919)

* Docs: Update email notifier documentation

Ref #21091

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

docs/sources/administration/provisioning.md

@@ -240,7 +240,7 @@ When Grafana starts, it will update/insert all dashboards available in the confi
 It's possible to make changes to a provisioned dashboard in the Grafana UI. However, it is not possible to automatically save the changes back to the provisioning source.
 If `allowUiUpdates` is set to `true` and you make changes to a provisioned dashboard, you can `Save` the dashboard then changes will be persisted to the Grafana database.
 
-> **Note.** 
+> **Note:**
 > If a provisioned dashboard is saved from the UI and then later updated from the source, the dashboard stored in the database will always be overwritten. The `version` property in the JSON file will not affect this, even if it is lower than the existing dashboard.
 >
 > If a provisioned dashboard is saved from the UI and the source is removed, the dashboard stored in the database will be deleted unless the configuration option `disableDeletion` is set to true.
@@ -415,6 +415,7 @@ The following sections detail the supported settings for each alert notification
 
 | Name |
 | ---- |
+| singleEmail |
 | addresses |
 
 #### Alert notification `hipchat`
@@ -463,4 +464,3 @@ The following sections detail the supported settings for each alert notification
 | Name |
 | ---- |
 | url |
-

docs/sources/alerting/notifications.md

@@ -71,14 +71,19 @@ external image destination if available or fallback to attaching the image to th
 Be aware that if you use the `local` image storage email servers and clients might not be
 able to access the image.
 
+Setting | Description
+---------- | -----------
+Single email | Send a single email to all recipients. Disabled per default.
+Addresses | Email addresses to recipients. You can enter multiple email addresses using a ";" separator.
+
 ### Slack
 
 {{< imgbox max-width="40%" img="/img/docs/v4/slack_notification.png" caption="Alerting Slack Notification" >}}
 
 To set up Slack, you need to configure an incoming Slack webhook URL. You can follow
-[their guide](https://api.slack.com/incoming-webhooks) on how to do that. If you want to include screenshots of the 
+[Sending messages using Incoming Webhooks](https://api.slack.com/incoming-webhooks) on how to do that. If you want to include screenshots of the
 firing alerts in the Slack messages you have to configure either the [external image destination](#external-image-store)
-in Grafana, or a bot integration via Slack Apps. Follow Slack's guide to set up a bot integration and use the token 
+in Grafana or a bot integration via Slack Apps. Follow Slack's guide to set up a bot integration and use the token
 provided (https://api.slack.com/bot-users), which starts with "xoxb".
 
 Setting | Description