Add test for reexported macros 2.0 rendering

Author: GuillaumeGomez

src/test/rustdoc/auxiliary/macro-2-reexport.rs

@@ -0,0 +1,6 @@
+#![crate_name = "macro_2_reexport"]
+#![feature(decl_macro)]
+
+pub macro addr_of($place:expr) {
+    &raw const $place
+}

src/test/rustdoc/macro-2-reexport.rs

@@ -0,0 +1,8 @@
+// aux-build: macro-2-reexport.rs
+
+#![crate_name = "foo"]
+
+extern crate macro_2_reexport;
+
+// @has 'foo/macro.addr_of.html' '//*[@class="docblock type-decl"]' 'macro addr_of($place : expr) {'
+pub use macro_2_reexport::addr_of;