rustdoc: add regression test for #140968

Author: lolbinarycat

tests/rustdoc-js/alias-rank-lower-140968.js

@@ -0,0 +1,10 @@
+// rank doc aliases lower than exact matches
+// regression test for <https://github.com/rust-lang/rust/issues/140968>
+
+const EXPECTED = {
+    'query': 'Foo',
+    'others': [
+        { 'path': 'alias_rank_lower', 'name': 'Foo' },
+        { 'path': 'alias_rank_lower', 'name': 'Bar' },
+    ],
+};

tests/rustdoc-js/alias-rank-lower-140968.rs

@@ -0,0 +1,6 @@
+#![crate_name = "alias_rank_lower"]
+
+pub struct Foo;
+
+#[doc(alias = "Foo")]
+pub struct Bar;