Expand parents whenever open-parenthesis comments are present (#6389)
## Summary
This PR modifies our dangling-open-parenthesis handling to _always_
expand the parent expression.
So, for example, given:
```python
a = int( # type: ignore
int( # type: ignore
int( # type: ignore
6
)
)
)
```
We now retain that as stable formatting, instead of truncating like:
```python
a = int(int(int(6))) # comment # comment # comment
```
Note that Black _does_ collapse comments like this _unless_ they're `#
type: ignore` comments, and perhaps in some other cases, so this is an
intentional deviation
([playground](https://black.vercel.app/?version=main&state=_Td6WFoAAATm1rRGAgAhARYAAAB0L-Wj4AFEAHpdAD2IimZxl1N_WlOfrjryFgvD4ScVsKPztqdHDGJUg5knO0JCdpUfW1IrWSNmIJPx95s0hP-pRNkCQNH64-eIznIvXjeWBQ5-qax0oNw4yMOuhwr2azvMRZaEB5r8IXVPHmRCJp7fe7y4290u1zzxqK_nAi6q_5sI-jsAAAAA8HgZ9V7hG3QAAZYBxQIAAGnCHXexxGf7AgAAAAAEWVo=)).