Consider using Ky to make our fetch examples better/more understandable

KY ("a tiny and elegant HTTP client based on the Fetch API") by [sindresorhus](https://github.com/sindresorhus) literally _just_ got a cool context API and [a bunch of options around retries](https://github.com/sindresorhus/ky?tab=readme-ov-file#retry) that are way more readable than the scary mess i suggest using at the bottom of this repo's README.

Since KY library is compatible with fetch, I suspect it would be trivial to pass it to `setFetchers` and give people a much easier and more understandable example of how to deal with timeouts retries etc.