RUF052 fix is unsafe when renaming function parameters

[dscorbett]

The fix for used-dummy-variable (RUF052) in Ruff 0.8.2 can introduce errors when renaming a function parameter. It should be marked unsafe in that context unless the parameter is positional-only.

$ cat ruf052.py
def f(_x):
    return _x
print(f(_x=1))

$ python ruf052.py
1

$ ruff check --isolated --preview --select RUF052 ruf052.py --fix
Found 1 error (1 fixed, 0 remaining).

$ cat ruf052.py
def f(x):
    return x
print(f(_x=1))

$ python ruf052.py
Traceback (most recent call last):
  File "ruf052.py", line 3, in <module>
    print(f(_x=1))
          ^^^^^^^
TypeError: f() got an unexpected keyword argument '_x'

[AlexWaygood]

Great catch @dscorbett. We can probably do two things here:

1. If we see that the binging comes from a function parameter, we can change the autofix so that it iterates through the uses of the function in the function's defining module and also changes those uses
2. If the function is explicitly marked as private to the module (the module has __all__ and the function does not appear in __all__), we can probably still mark it as safe if we do (1), but otherwise we'd have to mark it as unsafe if the binding comes from a parameter

[MichaReiser]

I like what you propose, but I think it might also just be fine to mark the fix as unsafe for now when the binding comes from a parameter (there are just so many things to consider; what if the function overrides another method?)