5100.7 section 5.2 "Job Description attributes that are defaults for the
Document(s) in the Job" is prescribing that the Printer MUST use these Job
Description attributes' values as the values for the corresponding Document
Description attributes in the case where the Client hasn't overtly
specified values for the individual Document objects in a Document creation
operation. This is not clearly obvious to a reader who wasn't involved in
this document's creation. The use of "default" in this context seems
different than the "xxx-default" convention from RFC 8011 etc.
Add a clarifying paragraph as per Ira McDonald's recommendation that
contrasts these two uses of "default"(i.e., apples and camels) so that
uninitiated readers in the future may more easily be able to meet 5100.7's
expectation if they are implementing an IPP Printer.