Drop support for dir-locals.nix, <nixpkgs>, etc.

In the spirit of Marie Kondo, I'm tidying up!

TL;DR:
- Prefer .envrc `use_nix` and delete all dir-locals.nix files
- Remove ~all references to <nixpkgs>, <unstable>, <depot> and prefer
  referencing each with briefcase.third_party.{pkgs,unstable,depot}
- Delete nixBufferFromShell function since I was only using that in
  dir-locals.nix files

1 files changed, 3 insertions, 6 deletions

diff --git a/scratch/groceries/shell.nix b/scratch/groceries/shell.nix
index c62b86e12832..4d5b412a0884 100644
--- a/scratch/groceries/shell.nix
+++ b/scratch/groceries/shell.nix
@@ -1,8 +1,5 @@
 let
-  pkgs = import <unstable> {};
-in pkgs.mkShell {
-  buildInputs = with pkgs; [
-    (haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
-    ]))
-  ];
+  briefcase = import <briefcase> {};
+in briefcase.buildHaskell.shell {
+  deps = hpkgs: [];
 }