Show the original footnote numbers and text when the page is printed

The previous behavior was to wrap footnote links and bodies in an inline `display: none`. Now these elements are given the style `footnote-print-only`, which is only displayed while printing. Conversely the Bigfoot ellipsis button is hidden during printing.

(If `actionOriginalFN` is `delete`, then all footnote-related elements are destroyed, just like before, and won't be displayed during printing. The ellipsis button is still hidden in this case.)