bug: Don't conflate passed argument with class member (instance attribute)

[pawamoy]

Description of the bug

In __init__ methods, when we do for example:

def __init__(self, arg: str) -> None:
    self.arg: str = arg
    """Description."""

Then Griffe thinks the arg value is the arg member, which it is not. It is an argument value, not a member of the current class.

This is annoying once docs are rendered, as the value will cross-reference to the member itself. The upcoming backlinks feature also suffers from it and will render a "used by" link pointing to itself.

Expected behavior

Griffe / mkdocstrings should not link such instance attribute values this way. I suppose it needs special casing somewhere 🤔

[pawamoy]

Oh, I think this is causing a lot of "Multiple secondary URLs" warnings from autorefs too. For example in https://mkdocstrings.github.io/griffe/reference/api/checks/#griffe.AttributeChangedValueBreakage.details the value is resolved as a name with a canonical path of _griffe.diff.Breakage.details, which has no primary URL and multiple secondary URLs.