Issue #19795: Mark up None as literal text.
diff --git a/Doc/library/select.rst b/Doc/library/select.rst
index ad7deec..7a08045 100644
--- a/Doc/library/select.rst
+++ b/Doc/library/select.rst
@@ -295,7 +295,7 @@
 
    Low level interface to kevent
 
-   - changelist must be an iterable of kevent object or None
+   - changelist must be an iterable of kevent object or ``None``
    - max_events must be 0 or a positive integer
    - timeout in seconds (floats possible)