tdf#92256: Make sure ref syntax of Excel docs gets saved
tdf#92256: Make sure ref syntax of Excel docs gets saved

SetStringRefSyntax guarantees that, as it sets also ScCalcConfig ->
mbHasStringRefSyntax to true

Change-Id: I44b4bd7854623a6229235ad0db9f0c4ddfbebe06

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