text: Title: Buttons in dialogs created by `Dialogs` should get keyboard shortcuts
  Body: #4619 proposed binding the `<Enter>` key to the `OK` button. That's a good idea, but we could also easily add separate keyboard shortcuts to all buttons. We can simply bind the first letter of each button (`OK`, `Cancel`, `PASS`, `FAIL`) to the same callback as the button. Should bind both the upper and the lower case versions so that pressing both `O` and `o` keys is the same as pressing the `OK` button.