.doc support for recently-added border line types

Some new border line types have been added recently to LibreOffice
(FINE_DASHED, DASH_DOT, DASH_DOT_DOT)

This change updates .doc import/export to support these.
(Import of FINE_DASHED was already working, but not export).

Change-Id: Id3bcb1d4e6e9ceb97b492f0c578fd5b885ab16ff
Reviewed-on: https://gerrit.libreoffice.org/8780
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>