Right now, our config rendering cannot handle childless non-leaf nodes. It always renders them as if they were valueless nodes:
```
utop # Vyos1x.Parser.from_string {|
system {
/* This is a non-leaf childless node */
login {
}
}
|} |> Config_tree.render_config |> Printf.printf "Rendered config:\n\n%s\n" ;;
Rendered config:
system {
/* This is a non-leaf childless node */
login
}
- : unit = ()
```
That can cause incorrect behavior and, and even when it doesn't, it's still wrong and breaks the expectation that parsed configs will be rendered exactly as they came.