devshell: Supress warnings by removing nested list

Author: 0y2k

nix/modules/devshell.nix

@@ -15,9 +15,9 @@
       '';
       buildInputs = [
         pkgs.libiconv
-      ] ++ lib.mapAttrsToList (_: crate: crate.crane.args.buildInputs) config.rust-project.crates;
+      ] ++ lib.concatMap (crate: crate.crane.args.buildInputs) (lib.attrValues config.rust-project.crates);
       packages = [
         toolchain
-      ] ++ lib.mapAttrsToList (_: crate: crate.crane.args.nativeBuildInputs) config.rust-project.crates;
+      ] ++ lib.concatMap (crate: crate.crane.args.nativeBuildInputs) (lib.attrValues config.rust-project.crates);
     };
 }