counting notes is per table, not on the whole document

Change-Id: Id4afa4eee961f159f8ea8caeac620d101cfb103e
Reviewed-on: https://gerrit.libreoffice.org/6941
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>