This issue tracks the release notes text for #130025.

• Proposed text is drafted by PR author (or team) making the noteworthy change.
• Issue is nominated for release team review of clarity for wider audience.
• Release team includes text in release notes/blog posts.

Release notes text:

The responsible team for the underlying change should edit this section to replace the
automatically generated link with a succinct description of what changed, drawing upon text
proposed by the author (either in discussion or through direct editing). If the change is notable
enough for inclusion in the blog post, add content to the blog section below.

# Compatibility Notes

 - The allow-by-default `missing_docs` lint used to disable itself when invoked through `rustc --test`/`cargo test`, resulting in `#[expect(missing_docs)]` emitting false positives due to the expectation being wrongly unfulfilled. This behavior [has now been removed](https://github.com/rust-lang/rust/pull/130025), which allows `#[expect(missing_docs)]` to be fulfilled in all scenarios, but will also report new `missing_docs` diagnostics for publicly reachable `#[cfg(test)]` items, [integration test](https://doc.rust-lang.org/cargo/reference/cargo-targets.html#integration-tests) crate-level documentation, and publicly reachable items in integration tests.

Note: The section title will be de-duplicated by the release team with other release notes issues.
Please use a standard title from previous releases.
More than one section can be included if needed.

Release blog section (if any, leave blank if no section is expected):

cc @Urgau, @petrochenkov -- origin issue/PR authors and assignees for starting to draft text