Add docs for default_intention_policy

website/content/docs/agent/config/config-files.mdx

@@ -447,6 +447,9 @@ Refer to the [formatting specification](https://golang.org/pkg/time/#ParseDurati
 
 - `data_dir` Equivalent to the [`-data-dir` command-line flag](/consul/docs/agent/config/cli-flags#_data_dir).
 
+- `default_intention_policy` Controls the default action for intentions. Can be
+  set to `allow`, `deny`, or left empty to default to [`acl.default_policy`](#acl_default_policy).
+
 - `disable_anonymous_signature` Disables providing an anonymous
   signature for de-duplication with the update check. See [`disable_update_check`](#disable_update_check).