Mention unused Battle Tower-related text (resolves #491)

maps/BattleTowerOutside.asm

@@ -105,6 +105,7 @@ BattleTowerOutsideSailorText:
 	done
 
 BattleTowerOutsideText_BattleTower:
+; unused; originally shown when the Battle Tower was closed
 	text "BATTLE TOWER"
 	done
 
@@ -116,11 +117,13 @@ BattleTowerOutsideText_UltimateChallenge:
 	done
 
 BattleTowerOutsideText_DoorsClosed:
+; unused; originally shown when the Battle Tower was closed
 	text "The BATTLE TOWER's"
 	line "doors are closed…"
 	done
 
 BattleTowerOutsideText_DoorsOpen:
+; unused; originally shown after the Battle Tower opened
 	text "It's open!"
 	done
 

maps/GoldenrodCity.asm

@@ -476,8 +476,8 @@ GoldenrodCityUndergroundSignSouthText:
 	line "ENTRANCE"
 	done
 
-PokeComCenterSignText:
-; unused in the english version
+GoldenrodCityPokeComCenterSignText:
+; unused
 	text "For Mobile Tips!"
 	line "#COM CENTER"
 	done

maps/OlivineCity.asm

@@ -281,7 +281,8 @@ OlivineCityBattleTowerSignText:
 	line "Opening Now!"
 	done
 
-UnknownText_0x1a8cba:
+OlivineCityBattleTowerSignText_NotYetOpen:
+; unused; originally shown when the Battle Tower was closed
 	text "BATTLE TOWER AHEAD"
 	done