Support DOCX exporting 'Track Changes - Deleted Paragraph Mark'

This patch adds support for the DOCX exporter to export the
'Track Changes' of type 'Deleted Paragraph Marker'.

Conflicts:
	sw/source/filter/ww8/docxattributeoutput.cxx
Reviewed on:
	https://gerrit.libreoffice.org/7061

Change-Id: Ia4f5933c9058d74fe8f47fc578747be972774340