Add endpoint links.

app/Api/V1/Controllers/Webhook/StoreController.php

@@ -55,6 +55,9 @@ class StoreController extends Controller
     }
 
     /**
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/webhooks/storeWebhook
+     *
      * @param CreateRequest $request
      *
      * @return JsonResponse