Rollup merge of #81575 - camelid:rustdoc-wrongnamespace-cleanup, r=jyn514

Rollup merge of #81575 - camelid:rustdoc-wrongnamespace-cleanup, r=jyn514

rustdoc: Name fields of `ResolutionFailure::WrongNamespace`

It makes it clearer that the `Namespace` is the one requested by the
disambiguator, rather than the actual namespace of the item. It said
that in the docs before, but now you can tell in the code so it reduces
the potential for confusion.