Mostly a tracking issue, here are the two related issues:

• RLS panics when opening a .rs diff #326 git:/, vanilla VS Code, occurs when opening a diff inside Source Control (Ctrl+Shift+G)
• vscode Perforce plugin causing RLS to crash #413 perforce://, VS Code + Perforce plugin, occurs when opening any .rs file

This directly occurs at lsp_data:27. Looked at it briefly and it seems that we need to convert urls to Path, since Vfs uses mostly that to deal with it file paths.

Since LSP uses URIs it'd be good to support more schemes or at least not panic right now when handling different ones. I understand that a proper solution would require more thought (e.g. how to deal with fragments, should we only care about scheme + authority + path?) but I think we should at least provide a simple non-crashing fix for now.

@nrc what should be preferred course of action here? Since URIs are guaranteed to be valid by LSP, maybe we could switch VFS' implementation to using URIs (and/or normalize them somehow behorehand) or just fake paths from different URI schemes and feed them as before to the VFS?

This would also probably allow to fix #299.