rustdoc: remove unused Hash impl

Author: notriddle

src/librustdoc/clean/types.rs

@@ -953,7 +953,7 @@ crate fn collapse_doc_fragments(doc_strings: &[DocFragment]) -> String {
 /// A link that has not yet been rendered.
 ///
 /// This link will be turned into a rendered link by [`Item::links`].
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 crate struct ItemLink {
     /// The original link written in the markdown
     crate link: String,