Construction macros don't work when nalgebra is aliased as na

If you alias `nalgebra` as `na` in Cargo.toml:

```
[dependencies]
...
na = { package = "nalgebra", version = "0.31", features = ["bytemuck"] }
...
```

The `point!` and `vector!` macros do not work.

Perhaps they internally use `nalgebra` instead of `$crate` as the path root?