make all same-module imports relative, the rest absolute

This makes sorting more consitent.

pkgs/clan-cli/clan_cli/nix/__init__.py

@@ -4,8 +4,8 @@ import tempfile
 from pathlib import Path
 from typing import Any
 
-from ..cmd import run, run_no_stdout
-from ..dirs import nixpkgs_flake, nixpkgs_source
+from clan_cli.cmd import run, run_no_stdout
+from clan_cli.dirs import nixpkgs_flake, nixpkgs_source
 
 
 def nix_command(flags: list[str]) -> list[str]: