Feature Request: Add Subtitle Concatenation Functionality

[zh00bc]

First off, thank you for your great work on this library. It has been very useful for handling subtitle files.

I would like to request a new feature that allows concatenating subtitle cues into a continuous sentence. This functionality would be beneficial for applications that need to display subtitles as a single, coherent text instead of individual cues.

Implementing this feature would enhance the library's capabilities and provide a convenient solution for developers working with subtitles.