Always create elided lifetimes, even if inferred.
`PathSource` gives the context in which a path is encountered. The same `PathSource` is used for the full path and the `QSelf` part.
Therefore, we can only rely on `PathSource` to know whether typechecking will be able to infer the lifetimes, not whether we need to insert them at all.
Fixes https://github.com/rust-lang/rust/issues/99949