Add documentation for the new arguments.

Authored-by: John Shahid <[email protected]>

Author: John Shahid

website/docs/r/alert_notification.html.md

@@ -17,6 +17,8 @@ resource "grafana_alert_notification" "email_someteam" {
   name = "Email that team"
   type = "email"
   is_default = false
+  send_reminder = true
+  frequency = "24h"
 
   settings {
     addresses = "[email protected];[email protected]"
@@ -32,6 +34,8 @@ The following arguments are supported:
 * `name` - (Required) The name of the alert notification channel.
 * `type` - (Required) The type of the alert notification channel.
 * `is_default` - (Optional) Is this the default channel for all your alerts.
+* `send_reminder` - (Optional) Whether to send reminders for triggered alerts.
+* `frequency` - (Optional) Frequency of alert reminders. Frequency must be set if reminders are enabled.
 * `settings` - (Optional) Additional settings, for full reference lookup [Grafana HTTP API documentation](http://docs.grafana.org/http_api/alerting).
 
 **Note:** In `settings` the strings `"true"` and `"false"` are mapped to boolean `true` and `false` when sent to Grafana.