PIE794 false positive when mutating class variable. Also leads to a bad fix.

[Skylion007]

class Person:
    name = "Foo"
    name = name + " Bar"

with unsafe fixes applied becomes:

class Person:
    name = "Foo"

It may not be the cleanest way of writing that, but it probably shouldn't trigger.

class Person:
    names = ["Foo"]
    names = names + ["Bar"]

is a use case I've actually seen in real code that probably should not be flagged.

ruff version is 0.1.4.

[Skylion007]

making it do += seems to be a decent mitigation for the objects which define it, but that may not always be an option depending on the Python object.