Today, mdbook doesn't show stderr when running Rust code. The problem is that it uses a Playground endpoint which doesn't deliver this information. However, the Playground itself does have this information via an internal endpoint. See rust-lang/mdBook#1315 for details.

Fixing this would allow us to start using dbg!(foo) instead of println!("foo: {foo:?}") in our code samples and thus simplify a lot of code blocks.

With google/mdbook-i18n-helpers#75 merged, many more code blocks would be automatically removed from the translation files, thus reducing churn for our translators.