Identify more bit flags (#1153)

docs/bugs_and_glitches.md

@@ -1297,7 +1297,7 @@ Pryce's dialog ("That BADGE will raise the SPECIAL stats of POKéMON.") implies
  .FutureSight:
 -; BUG: AI does not discourage Future Sight when it's already been used (see docs/bugs_and_glitches.md)
 -	ld a, [wEnemyScreens]
--	bit 5, a
+-	bit SCREENS_UNUSED, a
 +	ld a, [wEnemyFutureSightCount]
 +	and a
  	ret
@@ -2008,7 +2008,7 @@ Finally, edit [engine/battle/read_trainer_party.asm](https://github.com/pret/pok
 +	ld [wCurPartyLevel], a
 +
 +	ld a, [wInBattleTowerBattle]
-+	bit 0, a
++	bit IN_BATTLE_TOWER_BATTLE_F, a
 +	ret nz
 +
 +	ld a, [wLinkMode]

docs/design_flaws.md

@@ -248,7 +248,8 @@ Redefine the special music constants in [constants/music_constants.asm](https://
 
 ```diff
 -; GetMapMusic picks music for this value (see home/map.asm)
--DEF MUSIC_MAHOGANY_MART EQU $64
+-; this overlaps with a Crystal song ID, but not one that is used for map music
+-DEF MUSIC_MAHOGANY_MART EQU MUSIC_SUICUNE_BATTLE
 +; GetMapMusic picks music for these values (see home/map.asm)
 +DEF MUSIC_MAHOGANY_MART EQU $fc
 +DEF MUSIC_RADIO_TOWER   EQU $fd
@@ -256,10 +257,12 @@ Redefine the special music constants in [constants/music_constants.asm](https://
  ; ExitPokegearRadio_HandleMusic uses these values
  DEF RESTART_MAP_MUSIC EQU $fe
  DEF ENTER_MAP_MUSIC   EQU $ff
--
+
 -; GetMapMusic picks music for this bit flag
--DEF RADIO_TOWER_MUSIC_F EQU 7
--DEF RADIO_TOWER_MUSIC EQU 1 << RADIO_TOWER_MUSIC_F
+-	const_def 7
+-	shift_const RADIO_TOWER_MUSIC
+-assert NUM_MUSIC_SONGS <= RADIO_TOWER_MUSIC, "song IDs overlap RADIO_TOWER_MUSIC"
++assert NUM_MUSIC_SONGS <= MUSIC_MAHOGANY_MART, "song IDs overlap special values"
 ```
 
 Edit `GetMapMusic`: