Actually add home manager config

home/modules/applications/emacs/default.nix

@@ -0,0 +1,69 @@
+{ config, lib, pkgs, ... }:
+
+let
+  emacs = pkgs.emacs29;
+  doomSync = (let
+    git = pkgs.git;
+  in ''
+    export PATH=${emacs}/bin:${git}/bin:$PATH
+    ${config.xdg.configHome}/emacs/bin/doom sync -u -j $((`nproc`/4*3))
+  '');
+in {
+  home.packages = [
+    pkgs.emacs-all-the-icons-fonts
+    pkgs.fontconfig
+    pkgs.graphviz
+    pkgs.isort
+    pkgs.nerdfonts
+    pkgs.nil # nix lsp language server
+    pkgs.nixfmt-rfc-style
+    (pkgs.ripgrep.override {withPCRE2 = true;})
+    pkgs.pipenv
+    pkgs.poetry
+    pkgs.python3
+  ];
+
+  fonts.fontconfig.enable = true;
+
+  home.file = {
+    ".config/emacs" = {
+      source = fetchGit {
+        url = "https://github.com/doomemacs/doomemacs.git";
+        # When updating me, remember to run `doom sync`
+        rev = "36e7aaa619342eff61b1daf3ac664f94d5272db7";
+      };
+      # We need to use recursive mode here or else doom fails to sync for
+      # some reason related to the permissions on the synced path. I'm not
+      # quite sure of everything that's going on here.
+      recursive = true;
+
+      # Because `recursive = true` will cause this to sync every single
+      # activation, we turn this off here.
+      #
+      # There's probably a way we could do better detection of this within
+      # our onChange shell?
+      #
+      # onChange = doomSync;
+    };
+  };
+
+  home.sessionVariables = {
+    DOOMLOCALDIR = "${config.xdg.dataHome}/doom";
+    EDITOR = "emacs -nw";
+  };
+
+  home.sessionPath = [
+    "${config.xdg.configHome}/emacs/bin"
+  ];
+
+  programs.emacs = {
+    enable = true;
+    package = emacs;
+  };
+
+  xdg.configFile."doom" = {
+    source = ./doom;
+    # Sync doom if we updated the config
+    onChange = doomSync;
+  };
+}