Feature request: Add option to save each tag/caption on a separate line

[clayne]

Presently one can change the tag separator to another character. While I did not try it, I don't expect one can change it to a newline. There are some trainers that can alternate captions based on each line of the caption file (e.g. OneTrainer). This allows one to condition things differently while still keeping the various captions in order.

In fact it might be possible to extend this functionality to offer some kind of chunking similar to how various inference frontends split on 75 tokens for CLIP. As of right now I'm simply using a post-processing script to change the first comma to a newline with sed.