Mainly frees memory used by the document. Also closes a file, if it was not
closed before with ps_close. You should in any case
close the file with ps_close before, because
ps_close not just closes the file but also outputs a
trailor containing PostScript comments like the number of pages in the
document and adding the bookmark hierarchy.
Parameters
psdoc
Resource identifier of the postscript file
as returned by ps_new.