add cli to alert admonition (#1088)

Author: cjanslow

site/content/docs/alerting-and-retries/alert-channels.md

@@ -47,5 +47,5 @@ Configuring alert channels is mostly self explanatory except for our [advanced w
 After adding the channels, you either **edit** or **delete** them, or change which checks are subscribed to that specific channel.
 
 {{<info >}}
-If you are using [Terraform](/docs/terraform-provider/), you will need to specify alert channel subscriptions _explicitly_ for each check / group.
+If you are using [Terraform](/docs/terraform-provider/) or the [CLI](/docs/cli/), you will need to specify alert channel subscriptions _explicitly_ for each check / group.
 {{</info >}}