Fix markup.
diff --git a/Doc/whatsnew/3.0.rst b/Doc/whatsnew/3.0.rst
index 7332f14..d24416f 100644
--- a/Doc/whatsnew/3.0.rst
+++ b/Doc/whatsnew/3.0.rst
@@ -389,7 +389,8 @@
 
 * Everything is all in the details!
 
-* Developers can include intobject.h after Python.h for some PyInt_ aliases.
+* Developers can include :file:`intobject.h` after :file:`Python.h` for
+  some ``PyInt_`` aliases.
 
 .. ======================================================================