DeepLx支持

I'm not a native English speaker and I'm not very good with github. sorry if this causes any trouble or misunderstanding of the software design.

Some flaws encountered in use and suggestions that come to mind:

1. book management: suggest to add multi-select, file type filtering (or advanced search) and other functions.
2. translation: it is recommended to add deeplx translation services
3. statistics and notes: it is recommended to provide in addition to the deleted book information approach (I previously used the database editor to delete)
4. pdf support: the existing support is not smooth, there will be serious lag. Can you distinguish pdf parsing layout from others, using a single page scrolling?
5. data files: can you add the function of displaying the path where the data is located, so that manual management and the use of other software to open?

我并非英语母语者，也不擅长使用github。如果造成困扰，或对软件设计的理解失误，十分抱歉。

使用上遇到的一些缺陷及想到的建议：

1. 书籍管理：建议添加多选、文件类型筛选（或者高级搜索）等功能
2. 翻译：建议添加deeplx翻译服务
3. 统计及笔记：建议提供除了已删除书本信息的办法（我之前使用数据库编辑器删了）
4. pdf支持：现有支持并不流畅，会出现严重卡顿。能否将pdf解析排版与其它区分开来，使用单页滚动？
5. 数据文件：能否添加显示数据所在路径的功能，以便手动管理和使用其它软件打开？