[rustdoc-json] Add tests for #[doc(hidden)] handling of items.

[obi1kenobi]

Add tests which check:

• #[doc(hidden)] items are not present in rustdoc JSON output by default.
• Invoking rustdoc with --document-hidden-items makes #[doc(hidden)] items appear, and they show their #[doc(hidden)] status appropriately.

r? @aDotInTheVoid

[rustbot]

aDotInTheVoid is currently at their maximum review capacity.
They may take a while to respond.

[rustbot]

These commits modify tests/rustdoc-json.
rustdoc-json is a public (but unstable) interface.

Please ensure that if you've changed the output:

• It's intentional.
• The FORMAT_VERSION in src/librustdoc-json-types is bumped if necessary.

cc @aDotInTheVoid, @obi1kenobi

[obi1kenobi]

Removed the HTML test changes, only including the rustdoc JSON tests.

[aDotInTheVoid]

Thanks for writing these, really appreciate you doing the not glamours (but very important) work here.

Tests content is good, but I don't think they should live in tests/rustdoc-json/attrs, as they're not really testing the rendering of attributes, but the items we keep and don't. I think they'd be better suited to a (new) tests/rustdoc-json/visibility folder.

Also, could you edit the commit message to make it clear that this is specifically for rustdoc-json.

r=me with those nits addressed.

@bors delegate+

@bors rollup=always

[bors]

✌️ @obi1kenobi, you can now approve this pull request!

If @aDotInTheVoid told you to "r=me" after making some further change, please make that change, then do @bors r=@aDotInTheVoid

[obi1kenobi]

@bors r=aDotInTheVoid

[bors]

📌 Commit 27fb02c has been approved by aDotInTheVoid

It is now in the queue for this repository.