Support Alex ".x" files

## Is your enhancement request related to a problem? Please describe.

Currently, HLS fails when run on `.x` files:
```
2026-02-01T17:13:19-08:00 ERROR [project::lsp_store] Error handling response for request GetCodeLens: Code Lens via hls failed: No plugins are available to handle this SMethod_TextDocumentCodeLens request.
Plugins installed for this method, but not available to handle this request are:
eval does not support .x filetypes).
ghcide-type-lenses does not support .x filetypes).
importLens does not support .x filetypes).
class does not support .x filetypes).
moduleName does not support .x filetypes).
```

Unsure if this is a duplicate of #689, #4409

## Describe the solution you'd like

Right now, I just want HLS support on the Haskell part of the file.

## Describe alternatives you've considered

## Additional context