Recursion limit exceeded while visiting implicit joins

Given `a.py` that looks like

```
x = (
"a"
"a"
"a"
... 397 more of that line ...
)
```

`python -m usort check a.py` fails. The transformer is pretty straightforward, https://github.com/facebookexperimental/usort/blob/main/usort/sorting.py#L347

I'm not sure if replacing body is causing the problem, or if it does this for any transform involving many implicit string joins.