Add --reference-location=none

Perhaps enhance > --reference-location=block|section|document **|none|anchor:anchor_name** > >> Specify whether footnotes (and references, if reference-links is set) >> are placed at the end of the current (top-level). **"none" (or "ditch") means simply >> dispose of them, e.g., when in a [rush to make one's document >> shorter](https://superuser.com/questions/1937440/how-to-axe-all-footnotes-in-pandoc). >> However the footnote numbers will remain, so one might say >> "buy the deluxe version of my document to see the footnote bodies." >> You can also put all the footnotes at a certain (HTML) anchor.** In fact also add an option that blasts the footnotes entirely, as if we never wrote them.