[helix] can use project specific configuration in the `.helix` directory under
the project root. For gst-rs development, this can be used to select a group of
features:
.helix/languages.toml:
```toml
[language-server.rust-analyzer.config]
cargo = { features = ["v1_26"] }
```
It can also be used to configure debugging targets, thought debugging experience
with helix is lacking currently.
[helix]: https://helix-editor.com/
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1554>
