Rank by unmatched possessive-qualified phrases. If we have two unknown phrases, one with a possessive qualifier and one without, and other things being equal, prefer the one with the possessive qualifier.

We prefer the qualified version because it lets us report a smaller phrase that we can't match. For example, in X BOB'S WALLET, if we can't match WALLET all by itself, it's more useful to report that "you see no wallet" than to report that you see no "bob's wallet", because the latter incorrectly implies that there might still be a wallet in scope as long as it's not Bob's we're looking for.

rankByNonMatchPoss :   CommandRankingCriterion