Fix markup and working in the doc.
diff --git a/Doc/library/urllib.request.rst b/Doc/library/urllib.request.rst
index f99701d..3c02333 100644
--- a/Doc/library/urllib.request.rst
+++ b/Doc/library/urllib.request.rst
@@ -276,8 +276,8 @@
    :exc:`ValueError` when presented with an authentication scheme other than
    Digest or Basic.
 
-   ..versionchanged:: 3.3
-   Raise ValueError on unsupported Authentication Scheme.
+   .. versionchanged:: 3.3
+      Raise :exc:`ValueError` on unsupported Authentication Scheme.