integration-docs: Update Splunk for new doc format.

Part of zulip#29592.

zerver/webhooks/splunk/doc.md

@@ -1,13 +1,20 @@
+# Zulip Splunk integration
+
 See your Splunk Search alerts in Zulip!
 
+{start_tabs}
+
 1. {!create-channel.md!}
 
 1. {!create-an-incoming-webhook.md!}
 
-1. {!generate-integration-url.md!}
+1. {!generate-webhook-url-basic.md!}
 
-    If you do not specify a topic, the name of the search is used
-    (truncated to fit if needed).
+    !!! tip ""
+
+        If you do not specify a topic, the name of the search is used,
+        and will truncated if it exceeds the character limit for Zulip
+        topics.
 
 1. In the Splunk search app, execute the search you'd like to be
    notified about. Click on **Save As** in the top-right corner,
@@ -15,15 +22,21 @@ See your Splunk Search alerts in Zulip!
 
 1. Configure the **Settings** and **Trigger Conditions** for your search
    as appropriate. Under **Trigger Actions**, click **Add Actions**,
-   and select **Webhook**. Set **URL** to the URL constructed above,
+   and select **Webhook**. Set **URL** to the URL generated above,
    and click **Save**.
 
 !!! tip ""
 
     You can create as many search alerts as you like, with whatever
-    channel and topic you choose. Just update your webhook URL as
-    appropriate for each one, and make sure the channel exists.
+    channel and topic you choose. Just generate the webhook URL as
+    appropriate for each one.
+
+{end_tabs}
 
 {!congrats.md!}
 
 ![](/static/images/integrations/splunk/001.png)
+
+### Related documentation
+
+{!webhooks-url-specification.md!}