Handle file renames gracefully

I want to track the places where you reference a top-level module by name, so I can handle renaming automagically.

although maybe the language server protocol doesn't support that?

Start by checking whether the Language Server Protocol supports tracking references to top-level modules and rename operations. The issue names no files or tests; done would require an agreed approach that identifies those references and handles module renames automatically.

Written by the indexing model from the issue text.