Issue #19795: Mark up None as literal text.
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index 55733b9..c2af446 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -448,7 +448,7 @@
In addition to the above presentation types, integers can be formatted
with the floating point presentation types listed below (except
-``'n'`` and None). When doing so, :func:`float` is used to convert the
+``'n'`` and ``None``). When doing so, :func:`float` is used to convert the
integer to a floating point number before formatting.
The available presentation types for floating point and decimal values are: