Proposal: Switch http-types::error::Error.error from anyhow to eyre

https://lib.rs/crates/eyre is a fork of anyhow that uses the https://lib.rs/crates/backtrace instead of std::backtrace::Backtrace. the backtrace crate currently provides a much better interface than std::backtrace::Backtrace for programmatic interaction (iterating over frames, for example, allowing for backtrace filtering)

This is important for a web framework because the framework can provide a highly usable in-browser interface to understand errors. Here's an example from the phoenix framework:

In development mode, they render a relevant snippet of code and a backtrace annotated with filesystem locations. IIRC, clicking any of those stack frames jumps to that line, syntax highlighted, in browser. This is obviously way beyond what http-types, rust, and tide can currently offer, but switching to eyre and the backtrace crate would allow us to take further steps in that direction.