Which pages out of the ones written to the file to print. This is not indexed by the document pages,
but by the page number in the file.
E.g. if a document has 10 pages, we want pages 4-5 and 7, but only page 3-9 are in the file. This would contain 1-2 and 4. @see PageRangeUtils#computeWhichPagesInFileToPrint