doc only

Author: Mia-Cross

docs/resources/baremetal_server.md

@@ -321,6 +321,9 @@ In addition to all arguments above, the following attributes are exported:
     - `status` - The private network status.
     - `created_at` - The date and time of the creation of the private network.
     - `updated_at` - The date and time of the last update of the private network.
+- `private_ip` - The list of private IPv4 addresses associated with the resource.
+  - `id` - The ID of the IPv4 address resource.
+  - `address` - The private IPv4 address.
 - `ips` - (List of) The IPs of the server.
     - `id` - The ID of the IP.
     - `address` - The address of the IP.