fix: allow names to collide in the values/types namespaces

[asterite]

Description

Problem

Just something small I noticed that works in Rust but didn't in Noir.

Summary

The compiler stores types and values in separate namespaces yet when a path is looked up and the same name exists in both namespaces it returned just one of them (the one in values). So in the end that namespace separation, I think, was never really used.

Now when looking up a path we need to specify if we want to search in the type namespace or in the value namespace. The other namespace is still looked up as a fallback option if nothing is found on the target namespace so we can give errors like "foo is not a type, it's a function".

Additional Context

Documentation

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[asterite]

I asked for a review earlier but the implementation was too complex. Now I found a way to implement this in a much simpler way.

[jfecher]

Neat!