将程序添加到应用菜单

### 🥰 需求描述(Description)

添加一个`.desktop`文件以在应用程序菜单中启动

### 🧐 解决方案(Solution)

一个简陋的文件
```DESKTOP
[Desktop Entry]

Name=Watt Toolkit

Exec=/usr/local/bin/Steam++/Steam++.sh

Type=Application

Icon=/usr/local/bin/Steam++/Icons/Watt-Toolkit.png

Terminal=false
```
我把Stem++本体放在/usr/local/bin

Start with the requested .desktop file and the launcher and icon paths shown in the issue: /usr/local/bin/Steam++/Steam++.sh and /usr/local/bin/Steam++/Icons/Watt-Toolkit.png. Verify the desktop entry format and installation location; done means Watt Toolkit appears in the application menu and launches with the expected icon.

Written by the indexing model from the issue text.