Improve rust-analyzer support

[davidsemakula]

Description

Enables IDE features (e.g. completions, go to definition e.t.c) for internal compiler crates in rust-analyzer.

Fixes # (issue)
N/A

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• API change with a documentation update
• Additional test coverage
• Code cleanup or just keeping up with the latest Rustc nightly

N/A - Just a Cargo.toml config change.

How Has This Been Tested?

N/A

Checklist:

• Fork the repo and create your branch from main.
• If you've added code that should be tested, add tests.
• If you've changed APIs, update the documentation.
• Ensure the test suite passes.
• Make sure your code lints.

[hermanventer]

Great, thank you for doing this.