initial book structure for error handling book

[senyosimpson]

Keen to get some feedback on this 😃 At the moment, the structure is fairly high level. I think there's room for breaking things up into smaller chapters but I'm not sure what we should give its own chapter vs bundling into a larger chapter. I also tried to highlight what the talking points would be for each section - I will expand these to longer form descriptions once we have some more clarity through the discussions.

Let me know if I should add any reviewers, add tags, link an issue etc

[tlyu]

Thanks for fleshing this out! It seems like a good starting outline to me 🙂

I don't remember if I'd mentioned this to you before, but with using minigrep as the project through which many of the patterns will be showcased, I wrote up a blog post that does something similar, which we can use as a reference: https://github.com/seanchen1991/blog/blob/main/posts/extending-minigrep/index.md

Nice blog post! Thank you for writing it. Minor nit: when changing from thiserror to std::error, your new derive should probably be #[derive(Debug)], not #[derive(Error)] (which I think isn't available in libstd).