rustdoc doesn't link correctly to methods in trait implementations

[frewsxcv]

https://doc.rust-lang.org/nightly/std/?search=until

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[frewsxcv]

I learned via @QuietMisdreavus on IRC that they do have these methods via generic trait implementations, but the hyperlinks to the method definitions in the impls are broken.

[QuietMisdreavus]

The link anchors exist in the HTML, but they don't exist by default because the anchor is hidden by the automatic folding of trait implementations.

@GuillaumeGomez Should the search index links for trait implementations link to the trait impl itself now? Otherwise the link anchor goes nowhere and the user doesn't see where the method comes from.

[GuillaumeGomez]

I'll need to think about it.