We've added "wontfix" to the list of statuses that are regarded as "closed". The full list is now ['duplicate', 'invalid', 'resolved', 'wontfix'].
We decided against adding "on hold" to the list of statuses we consider "open". The number that appears in parens in the issues tab indicates the number of "open" issues. Issues that are on hold should not be included in this total since one of the main reasons for putting an issue on hold is to reduce the open issues count.