Nested expression formatting

[MichaReiser]

I was surprised that there's no existing issue for this.

We decided not to implement the following Black 24 style changes:

• parenthesize_long_type_hints,
• wrap_long_dict_values_in_parens
• parenthesize_conditional_expressions

Because a) implementing this in Ruff is kind of hard (or slow) and b) it goes against the overall goal to avoid unnecessary parentheses.

This Black issue goes into more detail about our concerns. We should explore different designs that yields better sub-expression formatting without requiring optional parentheses to improve readability.