Converts A && A.B into A?.B (#54342)

Implements the ?. operator, replacing code like A && A.B with A?.B

BYOND Ref:
When reading A?.B, it's equivalent to A && A.B except that A is only evaluated once, even if it's a complex expression like a proc call.

code/game/objects/structures/artstuff.dm

@@ -285,7 +285,7 @@
 
 /obj/structure/sign/painting/update_icon_state()
 	. = ..()
-	if(C && C.generated_icon)
+	if(C?.generated_icon)
 		icon_state = "frame-overlay"
 	else
 		icon_state = "frame-empty"
@@ -293,7 +293,7 @@
 
 /obj/structure/sign/painting/update_overlays()
 	. = ..()
-	if(C && C.generated_icon)
+	if(C?.generated_icon)
 		var/mutable_appearance/MA = mutable_appearance(C.generated_icon)
 		MA.pixel_x = C.framed_offset_x
 		MA.pixel_y = C.framed_offset_y

code/game/objects/structures/beds_chairs/alien_nest.dm

@@ -35,7 +35,7 @@
 					"<span class='notice'>You struggle to break free from the gelatinous resin... (Stay still for two minutes.)</span>",\
 					"<span class='hear'>You hear squelching...</span>")
 				if(!do_after(M, 1200, target = src))
-					if(M && M.buckled)
+					if(M?.buckled)
 						to_chat(M, "<span class='warning'>You fail to unbuckle yourself!</span>")
 					return
 				if(!M.buckled)

code/game/objects/structures/fireaxe.dm

@@ -51,7 +51,7 @@
 	else if(open || broken)
 		if(istype(I, /obj/item/fireaxe) && !fireaxe)
 			var/obj/item/fireaxe/F = I
-			if(F && F.wielded)
+			if(F?.wielded)
 				to_chat(user, "<span class='warning'>Unwield the [F.name] first.</span>")
 				return
 			if(!user.transferItemToLoc(F, src))

code/game/objects/structures/flora.dm

@@ -48,7 +48,7 @@
 /obj/structure/flora/tree/pine/Initialize()
 	. = ..()
 
-	if(islist(icon_states && icon_states.len))
+	if(islist(icon_states?.len))
 		icon_state = pick(icon_states)
 
 /obj/structure/flora/tree/pine/xmas

code/game/objects/structures/kitchen_spike.dm

@@ -102,7 +102,7 @@
 				"<span class='notice'>[user] is trying to pull you off [src], opening up fresh wounds!</span>",\
 				"<span class='hear'>You hear a squishy wet noise.</span>")
 			if(!do_after(user, 300, target = src))
-				if(M && M.buckled)
+				if(M?.buckled)
 					M.visible_message("<span class='notice'>[user] fails to free [M]!</span>",\
 					"<span class='notice'>[user] fails to pull you off of [src].</span>")
 				return
@@ -113,7 +113,7 @@
 			"<span class='hear'>You hear a wet squishing noise..</span>")
 			M.adjustBruteLoss(30)
 			if(!do_after(M, 1200, target = src))
-				if(M && M.buckled)
+				if(M?.buckled)
 					to_chat(M, "<span class='warning'>You fail to free yourself!</span>")
 				return
 		if(!M.buckled)

code/game/objects/structures/plasticflaps.dm

@@ -65,7 +65,7 @@
 		if(!M.ventcrawler && M.mob_size != MOB_SIZE_TINY)
 			return FALSE
 	var/atom/movable/M = caller
-	if(M && M.pulling)
+	if(M?.pulling)
 		return CanAStarPass(ID, to_dir, M.pulling)
 	return TRUE //diseases, stings, etc can pass