Optimize the readability of the code

res/levelGenerateData.txt

src/Animation/Animation.java

src/Level/BeginnerPanel.java

src/Level/Dialogue.java

src/Level/EndPanel.java

src/Level/Level.java

src/Level/LevelManager.java

src/Level/MakeLevel.java

src/Level/MyLevelManager.java

src/Level/SelectButton.java

src/Level/SelectPanel.java

src/Listener/MouseListener.java

src/Music/MusicPlayer.java

src/Page/GameStage.java

src/Page/LevelButton.java

src/Page/LevelPage.java

src/ShadowLifeGame.java

src/UI/Button.java

src/UI/Pane.java

src/UI/TestButton.java