nightly-2024-07-10: feat: lsp rename/find-all-references for local variables (#5439)

# Description

## Problem

Resolves #5458

## Summary

This wasn't working precisely for local variables. In particular, if you
had code like this:

```rust
let mut mutable_var = 1;
mutable_var = 2; <-- here
...
```

"go to definition" didn't work in the pointed line (assignments) and
previously "find all references" or "rename" didn't work at all.


https://github.com/noir-lang/noir/assets/209371/630d8440-3a2c-4621-9788-c8769f9afde9

## Additional Context

None.

## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.