Allow `nix build flake1 flake2 --update-input <Tab>` to complete the inputs of both flakes. Also do tilde expansion so that `nix build ~/flake --update-input <Tab>` works.
Allow `nix build flake1 flake2 --update-input <Tab>` to complete the inputs of both flakes. Also do tilde expansion so that `nix build ~/flake --update-input <Tab>` works.