Merge pull request #13441 from Putnam3145/shiver-fever-patch

Makes fever use the proper thresholds and shivering have thresholds at all.

code/datums/diseases/advance/symptoms/shivering.dm

@@ -32,7 +32,7 @@ Bonus
 		"Stage Speed 10" = "Further increases cooling speed."
 	)
 
-/datum/symptom/fever/Start(datum/disease/advance/A)
+/datum/symptom/shivering/Start(datum/disease/advance/A)
 	if(!..())
 		return
 	if(A.properties["stage_rate"] >= 5) //dangerous cold
@@ -58,4 +58,4 @@ Bonus
 	if(unsafe)
 		limit = 0
 	M.adjust_bodytemperature(-get_cold * A.stage, limit)
-	return 1
+	return 1