Both of them are abstractions over the css::style::NumberingType
constants.
SvxNumType serves no useful purpose, since it's just a typedef to
sal_Int16.
At least SvxExtNumType wraps up the css::style::NumberingType constants
in a nice enum.

Change-Id: I7b3f97cd42b0aa23aff7a4db4930da86149d4f4e
Reviewed-on: https://gerrit.libreoffice.org/34816Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>