菜单项添加快捷键

空格+下划线+键名

单个按键：

[MenuItem("Tools/my delete _d")]
    static void Delete()
    {
        Debug.Log("my delete");
    }

组合键:
%表示ctrl
#表示shift
&表示alt

[MenuItem("Tools/my delete _%m")]
    static void Delete()
    {
        Debug.Log("my delete");
    }