lsp: Treat unrooted paths as relative to the worktree root (#17769)
Piotr Osiewicz
and
Thorsten
created
gopls would send us watch patterns like `**/*.mod` and we'd fall back to
watching `/`.
Release Notes:
- Fix file watching for go projects resorting to watching the fs root.
Co-authored-by: Thorsten <thorsten@zed.dev>