rustdoc: "Copy Item Path" adds more nonsense

[aDotInTheVoid]

On https://doc.rust-lang.org/nightly/std/vec/struct.Vec.html clicking the "Copy Item Path to Clipboard" button copies std::vec - Rust::Vec, instead of std::vec::Vec

Version: 1.86.0-nightly (a567209 2025-02-13)

It works correctly on stable (1.84.1 (e71f9a9a9 2025-01-27) and beta 1.85.0-beta.9 (461de7492 2025-02-13).

[tapanprakasht]

@rustbot claim

[GuillaumeGomez]

Fixed in #137068.