Don't drop comments between items in TOML tables (#9784)
## Summary
If you look at Ed's reply
[here](https://github.com/toml-rs/toml/issues/818#issuecomment-2532626305),
it sounds like we're being too heavy-handed in applying `.fmt()`. I
think I added this to handle an issue with inline tables whereby we were
inserting a space after a trailing comma? So now I'm just applying
`.fmt()` to inline tables, which don't allow comments between elements
anyway.
Closes https://github.com/astral-sh/uv/issues/9758.
