Updated VNET support for Translator

Author: swmachan

articles/azure-government/documentation-government-services-aiandcognitiveservices.md

@@ -116,6 +116,9 @@ Variations in Azure Government:
 - Auth Token Service: 
      - https://usgovvirginia.api.cognitive.microsoft.us/sts/v1.0/issueToken
      - https://usgovarizona.api.cognitive.microsoft.us/sts/v1.0/issueToken
+- [Virtual Network support](../cognitive-services/cognitive-services-virtual-networks.md) for Translator service is limited to only US Gov Virginia region. The URI for accessing the API is:
+     - `https://<your-custom-domain>.cognitiveservices.azure.us`
+     - You can find your custom domain endpoint in the overview blade on the Azure portal once the resource is created.
 - Available SKUs: S1
 - Custom Translator and Translator Hub are not supported.