Merge pull request NixOS#275128 from Atemu/cleanup/packages-config

Revert "packages-config.nix: ignore haskellPackages.hs-mesos"

pkgs/top-level/packages-config.nix

@@ -12,6 +12,7 @@
       fdbPackages
       fusePackages
       gns3Packages
+      haskellPackages
       idrisPackages
       nodePackages
       nodePackages_latest
@@ -29,15 +30,6 @@
       zeroadPackages
     ;
 
-    haskellPackages = super.haskellPackages // {
-      # mesos, which this depends on, has been removed from nixpkgs. We are keeping
-      # the error message for now, so users will get an error message they can make
-      # sense of, but need to work around it here.
-      # TODO(@sternenseemann): remove this after branch-off of 22.05, along with the
-      # override in configuration-nix.nix
-      hs-mesos = null;
-    };
-
     # Make sure haskell.compiler is included, so alternative GHC versions show up,
     # but don't add haskell.packages.* since they contain the same packages (at
     # least by name) as haskellPackages.