treewide: replace nix_2_3 with nixVersions.nix_2_3

pkgs/development/libraries/boehm-gc/default.nix

@@ -1,9 +1,7 @@
 { lib, stdenv, fetchurl
 , autoreconfHook
 , enableLargeConfig ? false # doc: https://github.com/ivmai/bdwgc/blob/v8.0.6/doc/README.macros (LARGE_CONFIG)
-, nix
-, nix_2_3
-, nixUnstable
+, nixVersions
 }:
 
 stdenv.mkDerivation rec {
@@ -39,16 +37,7 @@ stdenv.mkDerivation rec {
 
   enableParallelBuilding = true;
 
-  passthru = {
-    tests = {
-      # Assuming this package is picked up by these packages as expected.
-      inherit
-        nix
-        nixUnstable
-        nix_2_3
-        ;
-    };
-  };
+  passthru.tests = nixVersions;
 
   meta = {
     description = "The Boehm-Demers-Weiser conservative garbage collector for C and C++";

pkgs/top-level/all-packages.nix

@@ -33307,7 +33307,7 @@ with pkgs;
 
   nix-linter = haskell.lib.compose.justStaticExecutables (haskellPackages.nix-linter);
 
-  nixos-option = callPackage ../tools/nix/nixos-option { nix = nix_2_3; };
+  nixos-option = callPackage ../tools/nix/nixos-option { nix = nixVersions.nix_2_3; };
 
   nix-pin = callPackage ../tools/package-management/nix-pin { };
 

pkgs/top-level/python-packages.nix

@@ -7921,7 +7921,7 @@ in {
   python-http-client = callPackage ../development/python-modules/python-http-client { };
 
   pythonix = callPackage ../development/python-modules/pythonix {
-    nix = pkgs.nix_2_3;
+    nix = pkgs.nixVersions.nix_2_3;
     meson = pkgs.meson.override { python3 = self.python; };
   };