* Refactor flake inputs because it's been annoying me for weeks now
* Fix a long-standing bug in mk_uniftype.rs
Can be reproduced by running `cargo test --workspace`.
This was never noticed before in CI because the `--workspace` flag is not passed.
This will be addressed in the Crane migration
* Remove utilities/Cargo.lock
This is probably a fragment of the past, back when Nickel did not use Cargo workspaces.
* Fix Clippy issues in tests
* Rustfmt and clippy are no longer in preview
* Update README with Nix flake shell command
* Migrate from import-cargo to crane for Nickel
Nickel WASM build is intentionally left intact and still uses the old
import-cargo.
This is because the change is already massive, and in practice the WASM build
relies more on `wasm-pack` than Cargo (even though under the hood, `wasm-pack`
uses Cargo).
If Crane looks good, both for DX and for CI, we will consider migrating Nickel
WASM to Crane too in a future PR.
* Remove support for Rust nightly channel
* Only Nix check for Rust `stable` channel
* Fix deprecated Nix build documentation commands
* Fix completion test
