Proper mirror PR for the disease refactor because I fucked up the first one. (#2026)

* Revert "im a dumbass and didn't see the .rej files Revert "[MIRROR] Disease Refactor" (#2025)"

This reverts commit 44742cb115.

* Delete shuttle_loan.dm.rej

* Delete life.dm.rej

* Update life.dm

* Delete life.dm.rej

* compile

code/game/data_huds.dm

@@ -62,7 +62,8 @@
 //called when a carbon changes virus
 /mob/living/carbon/proc/check_virus()
 	var/threat = 0
-	for(var/datum/disease/D in viruses)
+	for(var/thing in viruses)
+		var/datum/disease/D = thing
 		if(!(D.visibility_flags & HIDDEN_SCANNER))
 			if (D.severity != NONTHREAT) //a buffing virus gets an icon
 				threat = 2