fdo#75772 Correct name of Outline Numbering dialog

Change-Id: I14ffe5a9135f0fc37f839a386f4dc63c5831b9d4
Reviewed-on: https://gerrit.libreoffice.org/8875
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>