Replace V.slaves[V.slaveIndices] with getSlave() where possible

src/endWeek/saDevotion.js

src/facilities/nursery/utils/nurseryUtils.js

src/js/pregJS.js

src/npc/children/longChildDescription.js

src/npc/descriptions/longSlave.js

src/npc/generate/generateGenetics.js

src/npc/surgery/organFarm.js