fix bz424 - cannot wish for different size globs

fix bz424 - cannot wish for different size globs

Globs of pudding maintain an item quantity of 1 but vary in size
based on weight.  xname() formats with prefix of "small", <nothing>,
"large", and "very large" depending upon weight but wish processing
didn't recognize the prefix strings and reported "nothing fitting
that description exists".  Make wishing handle "small" (which is
actually the default), "medium" (since <nothing> isn't the default),
"large", and "very large".  They get ignored if the item isn't a
"glob of {gray ooze, brown pudding, black pudding, or green slime}".

Also, clean up recently added rnd_otyp_by_namedesc().