ESC key doesn't close confirmation modal windows

[RichardDavies]

The modal windows have a default close_aria_label text that says that the Escape key should close the window. But in my testing in Firefox and Chrome the Escape key does not actually close the window when using type=confirm.

To reproduce, use the confirmation modal on https://web.archive.org/web/20180626012005/http://humaan.com/modaal/