Add intra-doc-links to LinkedList rustdoc

Author: est31

library/alloc/src/collections/linked_list.rs

@@ -38,9 +38,12 @@ mod tests;
 /// let list = LinkedList::from([1, 2, 3]);
 /// ```
 ///
-/// NOTE: It is almost always better to use `Vec` or `VecDeque` because
+/// NOTE: It is almost always better to use [`Vec`] or [`VecDeque`] because
 /// array-based containers are generally faster,
 /// more memory efficient, and make better use of CPU cache.
+///
+/// [`Vec`]: crate::vec::Vec
+/// [`VecDeque`]: super::vec_deque::VecDeque
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "LinkedList")]
 pub struct LinkedList<T> {