Document some single-remaining symbols

src/battle_anim_dark.c

@@ -784,7 +784,7 @@ void AnimTask_InitMementoShadow(u8 taskId)
     DestroyAnimVisualTask(taskId);
 }
 
-void sub_8114470(u8 taskId)
+void AnimTask_MementoHandleBg(u8 taskId)
 {
     u8 toBG2 = GetBattlerSpriteBGPriorityRank(gBattleAnimAttacker) ^ 1 ? 1 : 0;
     ResetBattleAnimBg(toBG2);