I initially attempted to run `wasm-pack build -p ruff` which gave the
error message:
Error: crate directory is missing a `Cargo.toml` file; is `-p` the wrong
directory?
I interpreted that as wasm-pack looking for the "ruff" directory because
I specified -p ruff, however actually the wasm-pack build usage is:
wasm-pack build [FLAGS] [OPTIONS] <path> <cargo-build-options>
And I was missing the `<path>` argument. So this actually wasn't at all
a bug in wasm-pack but just a confusing error message. And the symlink
hack I introduced in the previous commit didn't actually work ... I only
accidentally omitted the `-p` when testing (which ended up as `ruff`
being the <path> argument) ... CLIs are fun.
