Remove dubbled entries when adding entries

src/add_command.ml

@@ -63,6 +63,7 @@ let run ~(rc:Rc.t) position =
   (* Create an updated rc file *)
   let updated_rc =
     rc#change_entries (new_list rc#entries position cmd_list)
+    |> Unify.prettify
   in
   updated_rc#write;
   (* Display the result *)