Update transfer_server.html.markdown

website/docs/r/transfer_server.html.markdown

@@ -99,7 +99,7 @@ The following arguments are supported:
 * `endpoint_details` - (Optional) The virtual private cloud (VPC) endpoint settings that you want to configure for your SFTP server. Fields documented below.
 * `endpoint_type` - (Optional) The type of endpoint that you want your SFTP server connect to. If you connect to a `VPC` (or `VPC_ENDPOINT`), your SFTP server isn't accessible over the public internet. If you want to connect your SFTP server via public internet, set `PUBLIC`.  Defaults to `PUBLIC`.
 * `invocation_role` - (Optional) Amazon Resource Name (ARN) of the IAM role used to authenticate the user account with an `identity_provider_type` of `API_GATEWAY`.
-* `host_key` - (Optional) RSA private key (e.g., as generated by the `ssh-keygen -N "" -m PEM -f my-new-server-key` command).
+* `host_key` - (Optional) RSA, ECDSA, or ED25519 private key (e.g., as generated by the `ssh-keygen -t rsa -b 2048 -N "" -m PEM -f my-new-server-key`, `ssh-keygen -t ecdsa -b 256 -N "" -m PEM -f my-new-server-key` or `ssh-keygen -t ed25519 -N "" -f my-new-server-key` commands).
 * `url` - (Optional) - URL of the service endpoint used to authenticate users with an `identity_provider_type` of `API_GATEWAY`.
 * `identity_provider_type` - (Optional) The mode of authentication enabled for this service. The default value is `SERVICE_MANAGED`, which allows you to store and access SFTP user credentials within the service. `API_GATEWAY` indicates that user authentication requires a call to an API Gateway endpoint URL provided by you to integrate an identity provider of your choice. Using `AWS_DIRECTORY_SERVICE` will allow for authentication against AWS Managed Active Directory or Microsoft Active Directory in your on-premises environment, or in AWS using AD Connectors. Use the `AWS_LAMBDA` value to directly use a Lambda function as your identity provider. If you choose this value, you must specify the ARN for the lambda function in the `function` argument.
 * `directory_id` - (Optional) The directory service ID of the directory service you want to connect to with an `identity_provider_type` of `AWS_DIRECTORY_SERVICE`.