fdo#79599: use \highlightN instead of \chcbpatN in RTF import and export

Reviewed on:
	https://gerrit.libreoffice.org/9776

Change-Id: I98ef606fb73368a3c275819cb83b936e2162769d
whitespace

Change-Id: I2db68597c83285571da2ddd1257a61a4603a90ef