Disabling formatting within a `proc` sometimes silently does not disable formatting

This:

```
proc p {
config() { }

init { }

// dslx-fmt::off
next(
state: ()) { () }
// dslx-fmt::on
}
```

will get formatted to:

```
proc p {
config() { }

init { }

// dslx-fmt::off
next(state: ()) { () }
// dslx-fmt::on
}
```

even though there was a request to disable formatting around the `next` method.

(Analysis; this happens due to the "ignore desugared functions" code added in c6c8197)