ruff

0bf5d2a2 - Revert "[ty] Use `invalid-assignment` error code for invalid assignments to `ClassVar`s" (#20158)

Revert "[ty] Use `invalid-assignment` error code for invalid assignments to `ClassVar`s" (#20158) Reverts astral-sh/ruff#20156. As @sharkdp noted in his post-merge review, there were several issues with that PR that I didn't spot before merging — but I'm out for four days now, and would rather not leave things in an inconsistent state for that long. I'll revisit this on Wednesday.