Copies page into Target as a new page object, without a Parent, for the target's page
tree.
public CosReference CopyPage(PdfPage page)
ISO 32000-2 §7.7.3.3, §7.7.3.4 and Table 31. Everything the page object holds is copied (contents, resources, annotations and what they
reach) except Parent; inherited attributes become the copy's own entries, and so does an Annots the page reads
from a page tree node (not inheritable, Table 31, but read as viewers read it; recorded as AnnotsInherited in the
source's diagnostics, so in strict mode this throws before the target changes). References to the page from inside the copied
graph (an annotation's P, say) name the copy. Place the reference in the target's page tree and set its Parent
for it to be a page of the target. A mutation of the target.