[KinoSearch] Scorer::doc

[Father Chrysostomos]

When is a Scorer’s doc method called? The WildCardQuery recipe  
implements this method, but, as far as I have been able to ascertain,  
the ‘next’ and ‘tally’ methods are called one after the other during a  
search, while ‘doc’ is not called at all. (???)

In the example in the cookbook, the first call to ‘next’ returns the  
first doc number, while ‘doc’ returns the doc number that the *next*  
call to ‘next’ will return. This doesn’t make sense to me. Is there a  
mistake in the cookbook?