rustdoc: tracking issue for improved path handling

[lolbinarycat]

looking through old rustdoc issue, there's a common theme of wanting to display or act on an item's canonical path instead of just its name.

unfortunately, this information is not easily available to the librustdoc render logic.

• Group navigation items in the docs by source crate/module #105307
• Improve rustdoc's Trait Implementations section by grouping by module #45260
• [rustdoc] type aliases in function signatures can be confusing #130189
• rustdoc: Documentation exposes the original private name instead of the public one #84367 (has more to do with canon names than paths, but still related)