Rollup merge of #143083 - JonathanBrouwer:rustdoc-fix, r=jdonszelmann

Fix rustdoc not correctly showing attributes on re-exports

Fixes attributes not being shown correctly in rustdoc on re-exports

Does this need to be backported to beta?

r? ``@jdonszelmann``

tests/rustdoc/attributes-re-export.rs

@@ -0,0 +1,13 @@
+// Tests that attributes are correctly copied onto a re-exported item.
+//@ edition:2021
+#![crate_name = "re_export"]
+
+//@ has 're_export/fn.thingy2.html' '//pre[@class="rust item-decl"]' '#[no_mangle]'
+pub use thingymod::thingy as thingy2;
+
+mod thingymod {
+    #[no_mangle]
+    pub fn thingy() {
+
+    }
+}