Add to doc a section highlighting the functionality or lack there of across the interfaces about bridgestan

[WardBrian]

The best place to do this is most likely on the "languages" landing page, no? https://roualdes.github.io/bridgestan/latest/languages.html

Something like

All language interfaces expose the same core functionality from the C API [link]. Additional "quality of life" features such as the ability to download BridgeStan's source code automatically or compile models from inside the language (rather than manually calling make) are available on a best-effort basis. If you are missing these features in your favorite language, we would welcome a contribution!

[roualdes]

Ya, I like that.

[bob-carpenter]

I like it, too and it's exactly what I think we should write in our doc.

For the article, I'd try to stay a bit more formal in tone than "we would welcome a contribution!" Given the space limitation, I suggest just dropping that last sentence, or at most, replacing it with some hint we might add more in the future.