What's the issue?

The amp-form component documentation currently has a blurb about redirecting after a submission, but it should be hidden when the currently-selected format is email. The "Redirecting after a submission" section is already hidden.

How do we reproduce the issue?

https://amp.dev/documentation/components/amp-form/?format=email#action-xhr has the following:

To learn about redirecting the user after successfully submitting the form, see the Redirecting after a submission section below.

That should be hidden.

/to @caroqliu