seo fix for missing meta description

Author: sffamily

articles/azure-signalr/index.yml

@@ -4,7 +4,7 @@ title: Azure SignalR Service Documentation
 metadata:
   document_id: 44409b3f-ab8c-053d-cdf4-5d7e823a275f
   title: Documentation - Azure SignalR Service
-  meta.description: Azure SignalR Service is an Azure managed service that helps developers easily build web applications with real-time features. This service is based on ASP.NET Core SignalR which is an open source library that simplifies adding real-time web functionality to applications.
+  description: Build and scale real-time web app easily in serverless or server mode. Based on WebSocket supporting broad range of languages and frameworks.
   services: azure-signalr
   author: v-chmccl
   manager: wesmc