Rustdoc doesn't explain (or can't) linking to slice methods

[Lokathor]

Rustdoc documentation tells you link to an item with [text](rust::path::to::item). You can even use paths appropriate to the current context to name an item, and so because i32 and other primitives are always in scope you can point a link at i32::abs or whatever. However, you seemingly can't direct a link at a method of a slice because you can't name the slice primitive type.

This is maybe just a docs issue, or maybe there needs to be special handling added in some way.

[jyn514]

Duplicate of #63351