combinators: minor improvement in usage example of case word
combinators: minor improvement in usage example of case word

mcandre/factor,mcandre/factor,mcandre/factor,erg/factor,erg/factor,mcandre/factor,mcandre/factor,mcandre/factor,erg/factor,erg/factor,erg/factor,erg/factor,erg/factor,mcandre/factor