Mark up one missed None in pkgutil.rst (#8851)
diff --git a/Doc/library/pkgutil.rst b/Doc/library/pkgutil.rst
index 35e81fe..fb79aef 100644
--- a/Doc/library/pkgutil.rst
+++ b/Doc/library/pkgutil.rst
@@ -77,8 +77,8 @@
newly created by a path hook.
If there is no importer, a wrapper around the basic import machinery is
- returned. This wrapper is never inserted into the importer cache (None is
- inserted instead).
+ returned. This wrapper is never inserted into the importer cache (``None``
+ is inserted instead).
The cache (or part of it) can be cleared manually if a rescan of
:data:`sys.path_hooks` is necessary.