Add TOTAL_HUDS define

Making a list just... 'be 10 long' is bad. Like update_icons layers and various other things, if you add more, it will compile fine and then you get runtimes later, which is a little annoying. Having places you just have to 'know' to update elsewhere in the code is meh.

code/__defines/misc.dm

@@ -36,6 +36,7 @@
 #define SPECIALROLE_HUD 8 // AntagHUD image.
 #define  STATUS_HUD_OOC 9 // STATUS_HUD without virus DB check for someone being ill.
 #define 	  LIFE_HUD 10 // STATUS_HUD that only reports dead or alive
+#define     TOTAL_HUDS 10 // Total number of HUDs. Like body layers, and other things, it comes up sometimes.
 
 //some colors
 #define COLOR_WHITE   			"#FFFFFF"

code/modules/mob/living/carbon/human/human.dm

@@ -5,7 +5,7 @@
 	icon = 'icons/mob/human.dmi'
 	icon_state = "body_m_s"
 
-	var/list/hud_list[10]
+	var/list/hud_list[TOTAL_HUDS]
 	var/embedded_flag	  //To check if we've need to roll for damage on movement while an item is imbedded in us.
 	var/obj/item/weapon/rig/wearing_rig // This is very not good, but it's much much better than calling get_rig() every update_canmove() call.
 	var/last_push_time	//For human_attackhand.dm, keeps track of the last use of disarm