[flake8-bugbear] Use typing.NamedTuple for data classes that only set attributes in an __init__ method (B903)

[jkauerl]

Summary

It semi-implements rule B903 from flake8-bugbear. The implementation is working but I need some clarifications regarding what is considerd a class that only set attributes in an __init__ method. This was implemented because it is rule to be implemented in #3758.

Test Plan

I implementeed the same test suite as the one located in flake8-bugbear, as such the should behave the same way.

Test suite:

class NoWarningsMoreMethods:
    def __init__(self, foo, bar):
        self.foo = foo
        self.bar = bar

    def other_function(self): ...


class NoWarningsClassAttributes:
    spam = "ham"

    def __init__(self, foo, bar):
        self.foo = foo
        self.bar = bar


class NoWarningsComplicatedAssignment:
    def __init__(self, foo, bar):
        self.foo = foo
        self.bar = bar
        self.spam = " - ".join([foo, bar])


class NoWarningsMoreStatements:
    def __init__(self, foo, bar):
        foo = " - ".join([foo, bar])
        self.foo = foo
        self.bar = bar


class Warnings:
    def __init__(self, foo, bar):
        self.foo = foo
        self.bar = bar


class WarningsWithDocstring:
    """A docstring should not be an impediment to a warning"""

    def __init__(self, foo, bar):
        self.foo = foo
        self.bar = bar

I want to add more test cases because the current implementation is a generalization.

[dylwil3]

The earlier PR #9601 ended up implementing this rule, which unfortunately makes this a duplicate. (You couldn't have known, since that PR was originally implementing a closely related pylint rule).

Apologies for the outcome and the long delay in resolving this, but thank you for your contribution and interest in Ruff - I hope this doesn't discourage you from contributing in the future!