clarify app namespace

Signed-off-by: Hannah Hunter <[email protected]>

Author: hhunter-ms

daprdocs/content/en/developing-applications/building-blocks/service-invocation/howto-invoke-discover-services.md

@@ -405,9 +405,9 @@ dapr invoke --app-id checkout --method checkout/100
 
 ### Namespaces
 
-When running on [namespace supported platforms]({{< ref "service_invocation_api.md#namespace-supported-platforms" >}}), you include the namespace of the target app in the app ID: `checkout.production`
+When running on [namespace supported platforms]({{< ref "service_invocation_api.md#namespace-supported-platforms" >}}), you include the namespace of the target app in the app ID. For example, following the `<app>.<namespace>` format, use `checkout.production`.
 
-For example, invoking the example service with a namespace would look like:
+Using this example, invoking the service with a namespace would look like:
 
 ```bash
 curl http://localhost:3602/v1.0/invoke/checkout.production/method/checkout/100 -X POST