don't localize toString()

Since `toString()` is mainly used for logging/debugging, I believe it should *not* localize. Otherwise, switching languages breaks logging and makes debugging harder. For example, many applications, especially in Node are going to be parsing their logs and it's weird to have different formats.

Since the docs and API are in English, I think it makes sense for it here. That said, I welcome feedback to the effect of "this will make it painful for me/others to debug, since I want that in my own language".

This is basically the opposite of #1018