chore: remove override to use rust syntax highlighting (#5881)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

Once github-linguist/linguist#7021 has been
deployed to github's internal systems we should have the Noir code in
this repository highlighted with our own grammar so this override will
be unnecessary.

## Additional Context



## 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.