rust: locked_by: shorten doclink preview

Increases readability by removing `super::` from the link preview
text.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-12-0c8af94ed7de@valentinobst.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

rust: sync: introduce `LockedBy`

This allows us to have data protected by a lock despite not being
wrapped by it. Access is granted by providing evidence that the lock is
held by the caller.

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230411054543.21278-13-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>