This project is still a WIP and is currently pre-release.
If you want to try using it check out the example and the dev dependencies for an idea how to setup spandoc + tracing.
If you run into broken line numbers its probably because of this issue https://github.com/rust-lang/rust/issues/43081,
#[spandoc] in particiular don't yet get along well. I have observed that putting the spandoc attribute above the tracing instrument one can sometimes fix broken line numbers. Proc macros /shrug.