Export redline 'paragraph formatting changes' back to DOCX

This patch adds support for the export of any redline of type
'paragraph formatting changes' properties that were imported from
a DOCX file under the 'pPrChange'->'pPr' XML node.

Reviewed on:
	https://gerrit.libreoffice.org/6993

Change-Id: Ieea5bbb219f444e382f22948944e038bb661ec7c