This PR adds the beginnings of current project context to the Assistant. Currently it supports reading a `Cargo.toml` file and using that to get some basic information about the project, and its dependencies: <img width="1264" alt="Screenshot 2024-05-14 at 6 17 03 PM" src="https://github.com/zed-industries/zed/assets/1486634/cc8ed5ad-0ccb-45da-9c07-c96af84a14e3"> Release Notes: - N/A --------- Co-authored-by: Nate <nate@zed.dev>