Adds a line in craft menu to signify book recipes

Recipes for which u.knows_recipe is false get a line "Recipe not memorized yet" below crafting ingredients, so that you don't have to either read descriptions from all your books or leave the books, open craft menu and search for the recipe just to check whether you know the recipe or not.

I thought about coloring all unmemorized recipes yellow (like books with unmemorized recipes are), but that could look ugly and I also couldn't think of a good color for unmemorized-and-unavailable recipes.
It would be more informative, while not being any harder to implement, though.