chore(3p/sources): Bump channels & overlays

Use nixos-unstable-small which fixes CVE-2018-25032
(out of bounds write while compressing).

* //users/grfn/xanthous:

  - Supporting random-fu 0.3 requires considerable changes and patching
    random-extras (https://github.com/aristidb/random-extras/pull/5).

    For now we downgrade random-fu and its dependency rvar to 0.2.*,
    forcing us to build xanthous with GHC 8.10.7, due to random-fu 0.2.*
    not supporting that version.

    Nix expressions for the downgraded packages are checked in to avoid
    the potential need to compile Haskell at pipeline eval time.

  - generic-arbitrary exposes a GenericArbitrary newtype now.
    This means we no longer have to implement it in xanthous
    downstream and patch generic-arbitrary to expose the
    GArbitrary type class.

  - Minor adjustments for lens 5.0:

    Xanthous.Game.Memo: clear needs to use ASetter' instead of Lens'

    Xanthous.Data.EntityMap: TraversableWithIndex no longer has an
    itraversed function.

  - Xanthous.Orphans: adjust for aeson's KeyMap, use KM.size explicitly
    instead of relying on MonoTraversable's length

* //nix/buildLisp: the CCL issue has resurfaced, disabling the
  implementation once again.

* //3p/arion: remove, as depot uses the nixpkgs package of it anyways.

* //users/wpcarro: accomodate GHC 9.0.1's stricter parsing of operators.

* //users/tazjin: disable rustfmt as it stopped respecting settings

* //3p/overlays: upgrade home-manager until fix for serivce generation
  has landed upstream

* //users/grfn/system: remove rr override, as the pinned commit is part
  of the 5.5.0 release shipped by nixpkgs.

Change-Id: If229e7317ba48498f85170b57ee9053f6997ff8a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5428
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Reviewed-by: wpcarro <wpcarro@gmail.com>

third_party/overlays/haskell/extra-pkgs/random-fu-0.2.nix

@@ -0,0 +1,41 @@
+{ mkDerivation
+, base
+, erf
+, lib
+, math-functions
+, monad-loops
+, mtl
+, random
+, random-shuffle
+, random-source
+, rvar
+, syb
+, template-haskell
+, transformers
+, vector
+}:
+mkDerivation {
+  pname = "random-fu";
+  version = "0.2.7.7";
+  sha256 = "8466bcfb5290bdc30a571c91e1eb526c419ea9773bc118996778b516cfc665ca";
+  revision = "1";
+  editedCabalFile = "16nhymfriygqr2by9v72vdzv93v6vhd9z07pgaji4zvv66jikv82";
+  libraryHaskellDepends = [
+    base
+    erf
+    math-functions
+    monad-loops
+    mtl
+    random
+    random-shuffle
+    random-source
+    rvar
+    syb
+    template-haskell
+    transformers
+    vector
+  ];
+  homepage = "https://github.com/mokus0/random-fu";
+  description = "Random number generation";
+  license = lib.licenses.publicDomain;
+}

third_party/overlays/haskell/extra-pkgs/rvar-0.2.nix

@@ -0,0 +1,25 @@
+{ mkDerivation
+, base
+, lib
+, MonadPrompt
+, mtl
+, random-source
+, transformers
+}:
+mkDerivation {
+  pname = "rvar";
+  version = "0.2.0.6";
+  sha256 = "01e18875ffde43f9591a8acd9f60c9c51704a026e51c1a6797faecd1c7ae8cd3";
+  revision = "1";
+  editedCabalFile = "1jn9ivlj3k65n8d9sfsp882m5lvni1ah79mk0cvkz91pgywvkiyq";
+  libraryHaskellDepends = [
+    base
+    MonadPrompt
+    mtl
+    random-source
+    transformers
+  ];
+  homepage = "https://github.com/mokus0/random-fu";
+  description = "Random Variables";
+  license = lib.licenses.publicDomain;
+}