Issue #19795: Mark up None as literal text.
diff --git a/Doc/library/json.rst b/Doc/library/json.rst
index bf88dca..9e3e05e 100644
--- a/Doc/library/json.rst
+++ b/Doc/library/json.rst
@@ -403,7 +403,7 @@
(to raise :exc:`TypeError`).
If *skipkeys* is false (the default), then it is a :exc:`TypeError` to
- attempt encoding of keys that are not str, int, long, float or None. If
+ attempt encoding of keys that are not str, int, long, float or ``None``. If
*skipkeys* is true, such items are simply skipped.
If *ensure_ascii* is true (the default), all non-ASCII characters in the