When the craft guide is showing a craft, the output slot is now a button,
which causes the craft guide to show ways in which that output can be
used. This mirrors the way input slots are buttons that show recipes
for the selected ingredient. Usages of an item can be iterated through
in the same way as recipes for the item. This incidentally offers some
ability to retrace one's steps through a crafting chain, without storing
actual history.
When the current craft guide item has no recipes, show a "no" symbol
instead of an ingredient grid, alongside the "No recipes" message.
When no item is selected in the craft guide, leave the recipe space empty.
