Add error message when trying to use &T as a type or &x as an expression

[jfecher]

Problem

Noir doesn't have immutable references but due to its similarity with Rust, users may try to use them anyway.

Happy Case

Users should get a nice error message indicating Noir doesn't have immutable references. Potentially with a link to docs or similar explaining why this is.

Project Impact

None

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response

[TomAFrench]

Agreed, we can likely have this as just a warning similar to the rust lint.