fix: skip redundant_field_names lint on macro-generated code

[waterWang]

Fixes #17525

redundant_field_names was firing on code generated by proc-macro derives (e.g., thiserror::Error), where the user cannot control the generated expansion. This adds a !field.span.from_expansion() guard to skip linting any code from macro expansions, including proc-macro derive output.

Changes

• clippy_lints/src/redundant_field_names.rs: added && !field.span.from_expansion() check
• tests/ui/redundant_field_names.rs: removed internal! macro lint expectation (now skipped by from_expansion() check)
• tests/ui/redundant_field_names.stderr: updated expected error count from 9 to 8

[rustbot]

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[jieyouxu]

Moderation note: user was suspended due to automated contributions (cf. rust-lang/rust#160788).

[blyxyas]

Hello @waterWang, seems that your account is automated (probably authored by some agent).
We are closing this pull request to leave easy first issues to new contributors.

Thanks for the warning, @jieyouxu!