Defining Part 4 - Code cleanup toward defines (... and the rest) (#19388)

* I wasn't done

* nits

code/game/objects/structures/crates_lockers/closets.dm

@@ -131,7 +131,7 @@
 	for(var/mob/M in loc)
 		if(itemcount >= storage_capacity)
 			break
-		if(istype(M, /mob/dead/observer))
+		if(isobserver(M))
 			continue
 		if(istype(M, /mob/living/simple_animal/bot/mulebot))
 			continue
@@ -243,7 +243,7 @@
 		return
 	if(user.loc==null) // just in case someone manages to get a closet into the blue light dimension, as unlikely as that seems
 		return
-	if(!istype(user.loc, /turf)) // are you in a container/closet/pod/etc?
+	if(!isturf(user.loc)) // are you in a container/closet/pod/etc?
 		return
 	if(!opened)
 		return