xmloff: add back the presumably accidentally removed "FootnoteLineStyle"
xmloff: add back the presumably accidentally removed "FootnoteLineStyle"

(regression from 7d9bb549d498d6beed2c4050c402d09643febdfa)

Change-Id: I67ec4516ff431efd47451ff07fc261ba32e80385

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core