Chase rename of ghostscript in the printing chapter.
The ghostscript port was split up into an X11-dependent and -independent
part in ports r395047. As a result, the print/ghostscript port no longer
exists, causing broken links in the printing chapter of the handbook.
Rename all occurances of print/ghostscript with print/ghostscript9-base to
fix the broken links.
Reported by: firstname.lastname@example.org
Ports info by: wosch@