Expand description of cool zone setting
Expand description of cool zone setting

It is apparently desirable to have more implementation detail in here.

Contributes to issue CURA-2795.

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