feat(users/Profpatsch/MyPrelude): add Pretty module

Change-Id: Id774963178ba358447699d0297a6a1fbef5ac8fe
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11240
Autosubmit: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/Profpatsch/my-prelude/default.nix

@@ -11,6 +11,7 @@ pkgs.haskellPackages.mkDerivation {
     ./src/MyPrelude.hs
     ./src/Test.hs
     ./src/Parse.hs
+    ./src/Pretty.hs
     ./src/Seconds.hs
     ./src/Tool.hs
     ./src/ValidationParseT.hs