Include "don't show again" checkbox on confirmations which support it.

[apocalyptech]

We've got a few confirmation dialogs which can be toggled off by the user, but most of them can currently only be set from the settings menu. The one which does include a "don't show again" checkbox right on the initial confirmation dialog is, I believe, deleting statements where there's only comments in the to-delete list.

Anyway, it'd be nice to add in a checkbox for all dialogs of that nature. Something to add to AdHocDialog.