changed` failed `for `payment_failed` on line 45
### What?
Error in line 45 on type of payment_intent
### Why?
Example provided does not work
### How?
Added 'payment_'
### What?
In the Payment Element demo, call
[`elements.update()`](https://stripe.com/docs/js/elements_object/update)
when the payment amount value is updated via slider. This ensures
wallets (Apple Pay, Google Pay) display the correct payment amount.
---------
Co-authored-by: Michael Novotny <manovotny@gmail.com>