Added documentation for Coqui Service and it's example.

[mdarshad928]

Hello.

I have added a few lines of documentation for Coqui services.

[osolmaz]

@mdarshad928 Thanks for the contribution. In the meanwhile since I added Coqui support, Coqui introduced an improved Python API which can be seen here: https://tts.readthedocs.io/en/latest/#python-api

That means we can get rid of all Coqui-related custom logic and use that API instead. Getting word boundaries might still be an issue though.

As I am too busy to tend to the library these days, would you be interested in helping out with this change?

[mdarshad928]

@mdarshad928 Thanks for the contribution. In the meanwhile since I added Coqui support, Coqui introduced an improved Python API which can be seen here: https://tts.readthedocs.io/en/latest/#python-api

That means we can get rid of all Coqui-related custom logic and use that API instead. Getting word boundaries might still be an issue though.

As I am too busy to tend to the library these days, would you be interested in helping out with this change?

Yeah, Surely. Let me go through the docs and I would certainly do the changes if I can.

Btw thanks for approving the pull request.

[osolmaz]

@mdarshad928 I've checked and Coqui indeed does not have word boundary support. I've created an issue for it here: https://github.com/coqui-ai/TTS/issues/2593

I think it's better if we deprecate the old logic before this feature is implemented on Coqui's side, since we already have the fallback word boundary detection through Whisper.

So I'd say go ahead. Here are some things that I had in mind to do:

• Delete all the Coqui cruft and simplify the service (would probably fit in a single file after the changes)
• Coqui had problematic dependencies and used to conflict with many other packages. That's why it was removed from pyproject.toml. If this issue has been resolved with the recent versions, let's add it back as an optional dependency that can be installed like pip install manim-voiceover[coqui]. You might need to do some trial and error with poetry.
• Configure Coqui service to fall back on Whisper word boundary detection. You can refer to e.g. GTTSService to see how this is done.

Feel free to create a PR and copy over this information there. Lmk if you have any questions.