chore(users/Profpatsch/my-prelude): vendor pa-json

Want to be able to make changes with low overhead, and having it in a
separate library is just annoying.

Change-Id: I30b76885d8e0e6ebaefe9506cf36672783ed4988
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12577
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/Profpatsch/my-prelude/default.nix

@@ -7,6 +7,8 @@ pkgs.haskellPackages.mkDerivation {
   src = depot.users.Profpatsch.exactSource ./. [
     ./my-prelude.cabal
     ./src/Aeson.hs
+    ./src/Json.hs
+    ./src/Json/Enc.hs
     ./src/Arg.hs
     ./src/AtLeast.hs
     ./src/MyPrelude.hs