Emit a notification related to the node position change, so the track changes
comment box is repositioned when the text node changes it's position.

Change-Id: I34b5ec453b3dc43895865f15d71aaead46ae6f24
Reviewed-on: https://gerrit.libreoffice.org/50640Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tamás Zolnai <tamas.zolnai@collabora.com>