Before this change I couldn't submit the dialog with return. Or
cmd+return.
From what I understand the problem was that the `TextEditor` always
steals the default focus. I tried a bunch of workarounds I found to set
the default focus on the button, but none of them worked.
Then I thought: do we even need a full-on Text*Editor*? So I switched
`TextEditor` to `Text` with a `ScrollView`: things look the same, text
is selectable and scrollable, but I can hit return to submit the dialog.
Instead of making a separate enum that must be translated from the
ClipboardRequest type, simply re-use ClipboardRequest to determine the
clipboard confirmation reason.