Fix warnings from "make check".
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index b535c22..807245f 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -417,7 +417,7 @@
    specific.
 
    If given, *default* will be returned if the object does not provide means to
-   retrieve the size.  Otherwise a `TypeError` will be raised.
+   retrieve the size.  Otherwise a :exc:`TypeError` will be raised.
 
    :func:`getsizeof` calls the object's ``__sizeof__`` method and adds an
    additional garbage collector overhead if the object is managed by the garbage