file extensions options for image viewing ui and downloads 在图片详情以及下载过滤中添加文件扩展名相关选项

[ChinaIceF]

Acknowledgements / 确认事项

• [X] I have updated to the latest version of the app / 已经更新到最新版
• [X] I have tried the FAQ / 试过FAQ了. FAQ
• [X] I have searched the existing issues and this is new ticket NOT a duplicate or related to another issue / 搜索过其他issue，确实不是重复问题
• [X] I will fill out the title and the information in this template / 填好标题和内容

What feature should be added? / 需要加上什么功能

如题，网页版的pixiv可以通过下载手段获取文件的类型 部分用户可能会对文件格式比较苛责，在图片详情页中加入这一提示或许是不错的选择 同时建议添加一个下载过滤器，可以以不同的tag或者文件格式为条件过滤下载的内容

Official support / 官方支持情况

• [ ] Is this feature supported by the official pixiv app? / 官方App是否支持

Is this feature supported by any other third-party pixiv app? / 第三方App是否支持

No response

Any other information can be help? / 其它信息

No response