Displays the result of a notmuch count query
default : unread emails wich path do not contained "Trash" (notmuch count "tag:unread AND NOT path:/.*Trash.*/")
Parameters:
notmuch_count.query: notmuch count query to show result
Errors:
if the notmuch query failed, the shown value is -1
Dependencies:
notmuch (https://notmuchmail.org/)
