Added wallrot event.

Also some updates to changelog.

code/modules/reagents/Chemistry-Reagents.dm

@@ -1214,6 +1214,17 @@ datum
 				..()
 				return
 
+			// Clear off wallrot fungi
+			reaction_turf(var/turf/T, var/volume)
+				if(istype(T, /turf/simulated/wall))
+					var/turf/simulated/wall/W = T
+					if(W.rotting)
+						W.rotting = 0
+						for(var/obj/effect/E in W) if(E.name == "Wallrot") del E
+
+						for(var/mob/O in viewers(W, null))
+							O.show_message(text("\blue The fungi are completely dissolved by the solution!"), 1)
+
 			reaction_obj(var/obj/O, var/volume)
 				if(istype(O,/obj/effect/alien/weeds/))
 					var/obj/effect/alien/weeds/alien_weeds = O

code/modules/reagents/reagent_containers/spray.dm

@@ -49,12 +49,20 @@
 
 	D.icon += mix_color_from_reagents(D.reagents.reagent_list)
 
+	var/A_turf = get_turf(A)
+
 	spawn(0)
 		for(var/i=0, i<3, i++)
 			step_towards(D,A)
 			D.reagents.reaction(get_turf(D))
 			for(var/atom/T in get_turf(D))
 				D.reagents.reaction(T)
+
+				// When spraying against the wall, also react with the wall, but
+				// not its contents.
+				if(get_dist(D, A_turf) == 1 && A_turf.density)
+					D.reagents.reaction(A_turf)
+				sleep(2)
 			sleep(3)
 		del(D)