Generate more descriptive paths for items which have the same name in Rustdoc

[RDambrosio016]

Currently rustdoc does not attempt to disambiguate between traits which have the same name and are used somewhere, say, implemented traits. This makes for an interesting time trying to figure out what it is actually implementing at a glance. The best example ive found is serde libraries and their Error struct: https://docs.serde.rs/serde_json/struct.Error.html#trait-implementations
It is not very easy to see what it is implementing at a glance. This could likely be solved by seeing if multiple names clash in the same "section" and if so, generating the full path. In which case it would generate something along the lines of

#73996 Could offer insights into how to implement this too.

[joshtriplett]

I would love to see this as well. An example from the standard library: https://doc.rust-lang.org/std/process/struct.Command.html . Notice how both impls of CommandExt look identical but refer to different traits.

[jhpratt]

Another example is the time crate, where traits are frequently implemented on both time::Duration and std::time::Duration. In some places, it will output the latter as StdDuration (due to aliased imports). Having this feature would be great and would provide a significant amount of clarity to end-users.

[jyn514]

Closing as duplicate of #42066 (wow, this is certainly reported a lot!)