Use paths and path-io

[alanz]

paths and path-io provide type-safe path handing.

[cronokirby]

Interested in working on this.

What's the extent of the modules that would be refactored to use this?

[alanz]

I think for a start see about using it wherever there is a FilePath in hie itself. This might lead into other modules, but we do not necessarily have to follow through all the way at first.

I would surmise it could lead into ghc-mod-core, and haskell-lsp/haskell-lsp-types.