Add missing space in translatable string

Change-Id: I88dabd5612069a7de3cad188344cc5c33ba22a7e
Reviewed-on: https://gerrit.libreoffice.org/13127
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>