Mention SignalR Service explicitly in NPM README (#12924)

Author: anthonychu

src/SignalR/clients/ts/signalr/README.md

@@ -1,4 +1,4 @@
-JavaScript and TypeScript clients for SignalR for ASP.NET Core
+JavaScript and TypeScript clients for SignalR for ASP.NET Core and Azure SignalR Service
 
 ## Installation
 
@@ -14,6 +14,8 @@ yarn add @microsoft/signalr
 
 See the [SignalR Documentation](https://docs.microsoft.com/aspnet/core/signalr) at docs.microsoft.com for documentation on the latest release. [API Reference Documentation](https://docs.microsoft.com/javascript/api/%40aspnet/signalr/?view=signalr-js-latest) is also available on docs.microsoft.com.
 
+For documentation on using this client with Azure SignalR Service and Azure Functions, see the [SignalR Service serverless developer guide](https://docs.microsoft.com/azure/azure-signalr/signalr-concept-serverless-development-config).
+
 ### Browser
 
 To use the client in a browser, copy `*.js` files from the `dist/browser` folder to your script folder include on your page using the `<script>` tag.