integration-docs: Update JSON formatter for new doc format.

Part of #29592.

zerver/webhooks/json/doc.md

@@ -1,17 +1,27 @@
+# Zulip JSON formatter
+
 Render JSON payloads nicely in a Zulip code block! This is
 particularly useful when you want to capture a webhook payload as part
 of [writing an incoming webhook
 integration](/api/incoming-webhooks-overview).
 
+{start_tabs}
+
 1. {!create-channel.md!}
 
 1. {!create-an-incoming-webhook.md!}
 
-1. {!generate-integration-url.md!}
+1. {!generate-webhook-url-basic.md!}
 
 1. Configure your application to send the webhook
    payload to the **URL** generated above.
 
+{end_tabs}
+
 {!congrats.md!}
 
 ![](/static/images/integrations/json/001.png)
+
+### Related documentation
+
+{!webhooks-url-specification.md!}