The private object of QTextDocument has been exposed through
public APIs marked internal, which we should avoid as much as
possible, since it clutters the headers.
For accessing private data without adding friends, we have
a nice pattern of adding a static get() function to the
private class itself.
Fixes: QTBUG-55059
Change-Id: I03e949a677e03487e95f24e3608a06aa0a3511ab
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
4724dfff62