#405 Post-Python 3: New Pub filer uses a misleading variable name for publication series

[Ahasuerus]

The "New Publication" filer, mod/pa_new.py, uses a misleading variable name, "NewPublisher", for publication series on lines 572, 584 and 587. It's presumably a result of copy-pasting the publisher-specific section (line 517-552) when publication series were implemented in the early 2010s.