Update `ruff_python_parser` README for crates.io (#26315)
## Summary
This PR updates the parser README to:
1. Link the parser README's AST reference to the published
`ruff_python_ast` crate
2. Remove the obsolete "Python version support" section now that version
specific syntax errors are implemented
Additionally, I've also updated the README generator to add a
"Versioning" section while preserving the rest of the handwritten README
and updated the generator to refresh marker-delimited versioning
sections. Maybe this is not worth doing, let me know if that's the case.
### Review
-
https://github.com/astral-sh/ruff/pull/26315/commits/5a4145a37436872c197c7de9771a04e91f4f0500
- updates the README manually as mentioned in (1) and (2) above
-
https://github.com/astral-sh/ruff/pull/26315/commits/dcb59253c41ecbebacd919defcbb725461a95478
- updates the README generator to add the versioning section
## Test plan
Here's the [Rendered
README](https://github.com/astral-sh/ruff/blob/dcb59253c41ecbebacd919defcbb725461a95478/crates/ruff_python_parser/README.md)
for preview.
Ran `uv run --script scripts/generate-crate-readmes.py` twice and
verified idempotent output
