Hasn't been needed for a while since the type-annots have been exposed
from core since `trio>=0.24`. Allows us to drop a buncha sub-deps as
well like,
- `async-generator`
- `importlib-metadata`
- `mypy-extensions`
- `typing-extensions`
- `zipp`
Yah, don't really know why i listed all those but..
Namely since i use `xonsh` for a main shell, this includes adding it as
well as related tooling. Obvi bump the `uv.lock`.
Some other stuff retained from `poetry` days,
- add usage-comments around various (optional) deps.
- add toml section separator lines.
- go with 2-space indent.
- add comment on `trio>0.27` needed for py3.13+