fix: rename folder lib/tests -> lib/test to be consistent with the attribute name

lib/test/minify.nix

@@ -0,0 +1,11 @@
+# This is a module to reduce the size of the NixOS configuration
+# Used by the tests
+# It unsets some unnecessary options
+{ lib, ... }:
+{
+  nixpkgs.flake.setFlakeRegistry = false;
+  nixpkgs.flake.setNixPath = false;
+  nix.registry = lib.mkForce { };
+  documentation.doc.enable = false;
+  documentation.man.enable = false;
+}