add sidenav entry

Author: forstisabella

src/_data/sidenav/main.yml

@@ -272,6 +272,8 @@ sections:
     title: Event Delivery
   - path: /connections/delivery-overview
     title: Delivery Overview
+  - path: /connections/alerting
+    title: Connections Alerting
   - path: /connections/find-writekey
     title: Locate Your Write Key
   - path: /connections/integration_error_codes