Improve documentation of completeConfigs
Improve documentation of completeConfigs

Contributes to issue CURA-1507.

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