Add regression test for doc alias matching vs equivalently matched items

tests/rustdoc-js/doc-alias-after-other-items.rs

@@ -0,0 +1,9 @@
+pub struct Foo;
+
+#[doc(alias = "Boo")]
+pub fn bar() {}
+
+pub struct Confiture;
+
+#[doc(alias = "Confiture")]
+pub fn this_is_a_long_name() {}