Add authenticationType

Author: jess-hu-340

articles/data-factory/connector-snowflake.md

@@ -157,7 +157,7 @@ The following properties are supported for a Snowflake linked service when using
 | :--------------- | :----------------------------------------------------------- | :------- | 
 | type             | The type property must be set to **Snowflake**.              | Yes      | 
 | connectionString | Specifies the information needed to connect to the Snowflake instance. You can choose to put password or entire connection string in Azure Key Vault. Refer to the examples below the table, as well as the [Store credentials in Azure Key Vault](store-credentials-in-key-vault.md) article, for more details.<br><br>Some typical settings:<br>- **Account name:** The  [full account name](https://docs.snowflake.net/manuals/user-guide/connecting.html#your-snowflake-account-name) of your Snowflake account (including additional segments that identify the region and cloud platform), e.g. xy12345.east-us-2.Azure.<br/>- **User name:** The login name of the user for the connection.<br>- **Database:** The default database to use once connected. It should be an existing database for which the specified role has privileges.<br>- **Warehouse:** The virtual warehouse to use once connected. It should be an existing warehouse for which the specified role has privileges.<br>- **Role:** The default access control role to use in the Snowflake session. The specified role should be an existing role that has already been assigned to the specified user. The default role is PUBLIC. | Yes      | 
-| authenticationType | Set this property to **Oauth**. | Yes      | 
+| authenticationType | Set this property to **Oauth**.<br>It supports External OAuth for Microsoft Azure AD. To learn more about this, see this [article](https://docs.snowflake.com/en/user-guide/oauth-ext-overview.html).| Yes      | 
 | oauthTokenEndpoint        | The Azure AD OAuth token endpoint. Sample: `https://login.microsoftonline.com/<tenant ID>/discovery/v2.0/keys`  | Yes       | 
 | clientId  | The application client ID supplied by Azure AD . | Yes      | 
 | clientSecret  | The client secret corresponds to the client ID.  | Yes      |