Add test for reexported hidden macro

tests/rustdoc/reexport-hidden-macro.rs

@@ -0,0 +1,22 @@
+// Ensure that inlined reexport of hidden macros is working as expected.
+// Part of <https://github.com/rust-lang/rust/issues/59368>.
+
+#![crate_name = "foo"]
+
+// @has 'foo/index.html'
+// @has - '//*[@id="main-content"]//a[@href="macro.Macro2.html"]' 'Macro2'
+
+// @has 'foo/macro.Macro2.html'
+// @has - '//*[@class="docblock"]' 'Displayed'
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! foo {
+    () => {};
+}
+
+/// not displayed
+pub use crate::foo as Macro;
+/// Displayed
+#[doc(inline)]
+pub use crate::foo as Macro2;