Note that the comment above 'deltas' merely removed, as it wasn't actionable
without changing the frontend, which can probably already deal with
multiple of these.
Now that types are better understood though, it was straightforward to
change the type of `file_path` to not be a string, which now is even
clearer of a necessity thanks to the `tauri`-independent `watcher` crate.
Also, remove a comment related to the lack of worktree support.
It now fails gracefully, and that will come up again if support should be added.
Previously, the attempt was made to enable only those `tokio` features
that are actually used. However, due to default-features still being
enabled and `tauri` using the `full` feature, for most intents and purposes
that wasn't effective.
Now default features are disabled, and `full` isn't used anymore, forcing
all crates to mention the exact features they need.
Note that `tracing` is missing here, as it wasn't effective previously
without the `--cfg tokio_unstable` option also being specified as rustflag.
