rustdoc: make trait methods findable with Ctrl-F

[jsha]

When looking at a struct or enum page, it's common to look for a method with Ctrl-F. This works if the method is part of an inherent implementation (that is, a method on the struct or enum itself). But if the method is part of a trait implementation, Ctrl-F won't find it because trait implementations are toggled closed by default.

I'm not sure of a great way to do this. Some ideas:

• Listen for Ctrl-F and temporarily open the toggles. Problems: This is probably flaky; it doesn't work when selecting "Find in page" from a menu; we probably wouldn't get any sort of even to know when to close them again.
• Implement our own in-page search, and override Ctrl-F. Personally I find it really unpleasant when pages do this; I think the browser functionality shouldn't be overridden.
• Make the trait implementation toggles opened by default. I don't know the pros/cons on this; I assume they are closed by default for a good reason.

[jyn514]

Make the trait implementation toggles opened by default. I don't know the pros/cons on this; I assume they are closed by default for a good reason.

This is my preference, people are often confused where to find functionality when it's hidden behind a trait.

[jsha]

It looks like this is the PR that added toggles for trait implementations, with links to some of the issues it was trying to solve: #47894. The PR has some discussion about hiding by default. It also links to some issues, like #40363.

[jsha]

Fixed in #86260