add optional region argument

Author: johnsonaj

website/docs/r/lakeformation_lf_tag_expression.html.markdown

@@ -46,6 +46,7 @@ The following arguments are optional:
 
 * `catalog_id` - (Optional) ID of the Data Catalog. Defaults to the account ID if not specified.
 * `description` - (Optional) Description of the LF-Tag Expression.
+* `region` - (Optional) Region where this resource will be [managed](https://docs.aws.amazon.com/general/latest/gr/rande.html#regional-endpoints). Defaults to the Region set in the [provider configuration](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#aws-configuration-reference).
 
 ## Attribute Reference