Link to the NEWS file from rustdoc.

src/doc.rs

@@ -26,6 +26,24 @@
 
 //! Documentation
 
+// Rust 1.54 stabilized invoking function-like macros in attributes.
+// We will use it after bumping MSRV.
+// #![feature(extended_key_value_attributes)],
+// #[doc = include_str!("../NEWS")]
+// pub mod news {}
+macro_rules! doc_module_with_external_source {
+    ($( #[$attr:meta] )*
+     $name: ident, $doc: expr) => {
+        $( #[$attr] )*
+        #[doc = ""]
+        #[doc = $doc]
+        pub mod $name {}
+    }
+}
+doc_module_with_external_source!(
+    /// # News
+    news, include_str!("../NEWS"));
+
 /// # Upgrade Guide
 ///
 /// ## Upgrade from 0.4.x to 0.5.x