Fix typo in documentation
Fix typo in documentation

Contributes to issue CURA-1911.

totalretribution/CuraEngine,totalretribution/CuraEngine,ROBO3D/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,ROBO3D/CuraEngine,Ultimaker/CuraEngine,totalretribution/CuraEngine,alephobjects/CuraEngine,alephobjects/CuraEngine,Ultimaker/CuraEngine