Change description of temperature settings to prevent confusion
Change description of temperature settings to prevent confusion

The term 'pre-heat' is now reserved for the actual pre-heating functionality.

Contributes to issue CURA-3161.

ynotstartups/Wanhao,ynotstartups/Wanhao,hmflash/Cura,hmflash/Cura,fieldOfView/Cura,Curahelper/Cura,Curahelper/Cura,fieldOfView/Cura