Feature Request: `split_after_opening_bracket=False`

I couldn't find a way to achieve this type of formatting (`manual_frmt` from below)

```python
unformatted = {"Jeanette Guy": 45, "Georgia Gabby": 53, "Ryland Juniper": 19,
"Celeste Lallie": 27, "Cherice Kaylee": 60, "Edward Tristen": 21, "Trinity
Roslyn": 38, "Linnie Aurora": 30, "Erik Devin": 39}

manual_frmt = {"Jeanette Guy": 45, "Georgia Gabby": 53, "Ryland Juniper": 19,
"Celeste Lallie": 27, "Cherice Kaylee": 60,
"Edward Tristen": 21, "Trinity Roslyn": 38,
"Linnie Aurora": 30, "Erik Devin": 39}

best_effort = {
"Jeanette Guy": 45, "Georgia Gabby": 53, "Ryland Juniper": 19,
"Celeste Lallie": 27, "Cherice Kaylee": 60, "Edward Tristen": 21,
"Trinity Roslyn": 38, "Linnie Aurora": 30, "Erik Devin": 39}
```

Start by tracing YAPF's formatting handling for opening brackets and compare its output with the unformatted, manual_frmt, and best_effort examples in the issue. Done means a configurable split_after_opening_bracket=False behavior produces the requested formatting while existing formatting behavior remains unchanged.

Written by the indexing model from the issue text.