Clarify in the book when rustdoc tests are run #24228
Description
The new chapter on documentation is great, but in my opinion the documentation tests are still missleading.
When you
- create a crate with
cargo new --bin mycrate - write a doc test
- run
cargo test
it will not run this doctest, only if the create was created without the --bin flag. This behaviour is documented in the crates manifest but this should be noted directly in the book. Particularly as I think, most readers of the book will play around with a project with a main.rs but not with a lib.rs.