Don't lint about missing code examples in derived traits

[hnj2]

When the missing_doc_code_examples lint is performed it also requires that derived Trait implementations have a code example for each member etc., which causes undesirable behavior.

Examples

With missing_doc_code_examples enable we are not able to use the Clone derive macro due to the generated code not being documented:

#[deny(rustdoc::missing_doc_code_examples)]

/// docs
/// ```
/// let s = SomeStruct;
/// ```
#[derive(Clone)]
pub struct SomeStruct;

yields:

 Documenting testt v0.1.0 (<redacted>)
error: missing code example in this documentation
 --> src/lib.rs:7:10
  |
7 | #[derive(Clone)]
  |          ^^^^^
  |
note: the lint level is defined here
 --> src/lib.rs:1:8
  |
1 | #[deny(rustdoc::missing_doc_code_examples)]
  |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: missing code example in this documentation
 --> src/lib.rs:7:10
  |
7 | #[derive(Clone)]
  |          ^^^^^

error: could not document `testt`

Caused by:
  process didn't exit successfully: `rustdoc ...

closes #81775

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @CraftSpider (or someone else) soon.

Please see the contribution instructions for more information.

[hnj2]

Hey, since you reviewed #88745 could you take a look at this? Thanks

r? @GuillaumeGomez

[GuillaumeGomez]

This is a really nice fix, thanks!

Don't hesitate to ping me or @jyn514 sooner next time. ;)

@bors: r+

[bors]

📌 Commit 5f464bb has been approved by GuillaumeGomez