Problem: `nvim://` scheme feels more like a generalized interface that
may be requested externally, and it acts like CLI args (roughly).
This is how `vscode://` works.
Anything that behaves like an "app" or a "protocol" deserves its own
scheme. For such Nvim-owned things they will be called `nvim-xx://`.
Solution: Use `nvim-pack://confirm#<bufnr>` template for confirmation
buffer name instead of `nvim://pack-confirm#<bufnr>`.
f492f62c3d
