ruff

f58a54f0 - Move `red_knot_python_semantic::PythonVersion` to the `ruff_python_ast` crate (#16147)

Move `red_knot_python_semantic::PythonVersion` to the `ruff_python_ast` crate (#16147) ## Summary This PR moves the `PythonVersion` struct from the `red_knot_python_semantic` crate to the `ruff_python_ast` crate so that it can be used more easily in the syntax error detection work. Compared to that [prototype](https://github.com/astral-sh/ruff/pull/16090/) these changes reduce us from 2 `PythonVersion` structs to 1. This does not unify any of the `PythonVersion` *enums*, but I hope to make some progress on that in a follow-up. ## Test Plan Existing tests, this should not change any external behavior. --------- Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>