fix(lsp): use file uris for neovim virtual definitions (#34653)

Closes denoland/divybot#387
Fixes https://github.com/denoland/deno/issues/28794

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Co-authored-by: divybot <divybot@users.noreply.github.com>
Co-authored-by: Divy Srivastava <me@littledivy.com>