Checks that the prefix of the document number (upto the first "-") is included in
this list of scopes as given by the scope control.
This is a PostFilter, so new_query() is called for each new query, and filter()
is called for each result in the resultset.
Fields inherited from interface org.terrier.querying.PostFilter
Called for each result in the resultset, used to filter out unwanted results,
based on the presence of some strings in the document number. The document number
upto the first "-" is checked for presence in the scopes HashSet.