ui.gadgets.worlds: remove fonts slot from docs.
FUEL: Error message is now shown if word can't be found.
FUEL: Put several more characters that can be used in word names in the symbols class
FUEL: Correct regexp to work with multiline USING:
FUEL: Make fuel-help (C-c C-d d) work for vocabularies too.
FUEL: Tables in help buffers must be plain ascii to be correctly rendered everywhere.