Trailing commas in function params cause line splits in type params instead

[sumezulike]

Describe the bug

A function with type parameters gets formatted incorrectly if the function parameters have a magic trailing comma.

To Reproduce

For example, take this code:

def func1[T](a,): pass
def func3[T,](a,): pass
def func3[T,](a,) -> R[X, Y,]: pass

And run it with these arguments:

$ black file.py --target-version py312

The resulting code is:

def func1[
    T
](a,):
    pass


def func3[
    T,
](a,):
    pass


def func3[
    T,
](a,) -> R[
    X,
    Y,
]:
    pass

The type parameters are split instead of the function parameters.

Expected behavior

I would expect this result.

def func1[T](
    a,
):
    pass


def func2[
    T,
](
    a,
):
    pass


def func3[
    T,
](
    a,
) -> R[
    X,
    Y,
]:
    pass

Environment

$ black --version black, 24.2.0 (compiled: yes) Python (CPython) 3.12.1

Additional context

I am currently drafting a PR to fix this bug. My current approach is to rework should_split_funcdef_with_rhs to also check for the position of the trailing comma in type and function parameters. If I am overlooking something with that approach or if you have a better idea on how to fix this, please feel free to let me know.