Note in docs clarifying the supported operation modes for Domain Serv…

…ices

website/docs/d/active_directory_domain_service.html.markdown

@@ -10,6 +10,8 @@ description: |-
 
 Gets information about an Active Directory Domain Service.
 
+-> **Supported Modes:** At present this data source only supports **User Forest** mode and _not_ **Resource Forest** mode. [Read more](https://docs.microsoft.com/en-us/azure/active-directory-domain-services/concepts-resource-forest) about the different operation modes for this service.
+
 ## Example Usage
 
 ```hcl

website/docs/r/active_directory_domain_service.html.markdown

@@ -10,7 +10,9 @@ description: |-
 
 Manages an Active Directory Domain Service.
 
-~> Implementation Note: Before using this resource, there must exist in your tenant a service principal for the Domain Services published application. This service principal cannot be easily managed by Terraform and it's recommended to create this manually, as it does not exist by default. See [official documentation](https://docs.microsoft.com/en-us/azure/active-directory-domain-services/powershell-create-instance#create-required-azure-ad-resources) for details.
+~> **Implementation Note:** Before using this resource, there must exist in your tenant a service principal for the Domain Services published application. This service principal cannot be easily managed by Terraform and it's recommended to create this manually, as it does not exist by default. See [official documentation](https://docs.microsoft.com/en-us/azure/active-directory-domain-services/powershell-create-instance#create-required-azure-ad-resources) for details.
+
+-> **Supported Modes:** At present this resource only supports **User Forest** mode and _not_ **Resource Forest** mode. [Read more](https://docs.microsoft.com/en-us/azure/active-directory-domain-services/concepts-resource-forest) about the different operation modes for this service.
 
 ## Example Usage