add nixpkgs ndg, remove substituter

flake.nix

@@ -1,12 +1,6 @@
 {
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
-    ndg.url = "github:feel-co/ndg";
-  };
-
-  nixConfig = {
-    substituters = [ "https://feel-co.cachix.org" ];
-    trusted-public-keys = [ "feel-co.cachix.org-1:nwEFNnwZvtl4KKSH5LDg+/+K7bV0vcs6faMHAJ6xx0w=" ];
   };
 
   # cheerfully lifted from nixos + hjem-rum doc gen
@@ -122,14 +116,12 @@
             let
               json = self.lib.json args;
             in
-            pkgs.runCommandLocal "${projectName}-docs"
-              { nativeBuildInputs = [ ndg.packages.${pkgs.system}.ndg ]; }
-              ''
-                ndg --verbose html --jobs $NIX_BUILD_CORES --title "${projectName}" \
-                  --module-options "${json}" \
-                  --generate-search \
-                  --output-dir "$out"
-              '';
+            pkgs.runCommandLocal "${projectName}-docs" { nativeBuildInputs = [ pkgs.ndg ]; } ''
+              ndg --verbose html --jobs $NIX_BUILD_CORES --title "${projectName}" \
+                --module-options "${json}" \
+                --generate-search \
+                --output-dir "$out"
+            '';
         };
     };
 }