Update ai.md

[piedoom]

I've added a few things here. First is to call out AI use in accessibility as acceptable use. Second is to note that Rust Audio is not really any central org, and that repo owners may have their own rules. Third, I add that users should avoid personally investigating/arguing with supposed abusers both because it creates noise for moderators & may not even be an issue, depending on the use-case or maintainer.

Let me know your thoughts.

[roderickvd]

Thanks for finding a way in spirit of #15.

Rather than adding review comments to this PR, I created a gist with a proposed redaction: https://gist.github.com/roderickvd/b522bf291ede781899f9f75cf95e1b39

One major thought is to have repositories "overload" the generic RustAudio AI policy through their own README.md or CONTRIBUTING.md. That should be more:

• scalable than maintaining a list of exceptions here
• accommodating to people like me, who besides cpal also co-maintain Rodio and dasp

Anything to your liking?