Bug: parentheses not being eliminated

Parenthesis are not being eliminated. OCamlformat 0.19. I expect that they should. Am I wrong?

```ocaml
let __ = (get_op op) e_lhs
```

```ocaml
➜  /tmp ocamlformat /tmp/xxx.ml --enable-outside-detected-project
let __ = (get_op op) e_lhs
```
Standart configuration, no `.ocamlformat` file.