chore: add alejandra to nix shell

flake.nix

@@ -35,7 +35,7 @@
     in {
       inherit formatter;
       devShells.default = import ./shell.nix {
-        inherit pkgs nil;
+        inherit pkgs nil formatter;
       };
     };
   in

shell.nix

@@ -1,13 +1,15 @@
 {
-  pkgs,
+  formatter,
   nil,
+  pkgs,
   ...
 }:
 with pkgs;
   mkShell {
     buildInputs = [
+      formatter
+      git-cliff
       nil
       sumneko-lua-language-server
-      git-cliff
     ];
   }