docs/data-source/aws_api_gateway_rest_api: Alphabetize attributes and…

… add missing execution_arn attribute

Reference: #10971

website/docs/d/api_gateway_rest_api.html.markdown

@@ -27,14 +27,14 @@ data "aws_api_gateway_rest_api" "my_rest_api" {
 
 ## Attributes Reference
 
-* `id` - Set to the ID of the found REST API.
-* `arn` - The ARN of the REST API.
-* `root_resource_id` - Set to the ID of the API Gateway Resource on the found REST API where the route matches '/'.
-* `description` - The description of the REST API.
 * `api_key_source` - The source of the API key for requests.
-* `policy` - JSON formatted policy document that controls access to the API Gateway.
-* `minimum_compression_size` - Minimum response size to compress for the REST API.
+* `arn` - The ARN of the REST API.
 * `binary_media_types` - The list of binary media types supported by the REST API.
+* `description` - The description of the REST API.
 * `endpoint_configuration` - The endpoint configuration of this RestApi showing the endpoint types of the API.
+* `execution_arn` - The execution ARN part to be used in [`lambda_permission`](/docs/providers/aws/r/lambda_permission.html)'s `source_arn` when allowing API Gateway to invoke a Lambda function, e.g. `arn:aws:execute-api:eu-west-2:123456789012:z4675bid1j`, which can be concatenated with allowed stage, method and resource path.
+* `id` - Set to the ID of the found REST API.
+* `minimum_compression_size` - Minimum response size to compress for the REST API.
+* `policy` - JSON formatted policy document that controls access to the API Gateway.
+* `root_resource_id` - Set to the ID of the API Gateway Resource on the found REST API where the route matches '/'.
 * `tags` - Key-value mapping of resource tags.
-