Issue #19795: Mark up None as literal text.
diff --git a/Doc/library/formatter.rst b/Doc/library/formatter.rst
index e696fec..9773908 100644
--- a/Doc/library/formatter.rst
+++ b/Doc/library/formatter.rst
@@ -344,7 +344,7 @@
.. class:: DumbWriter(file=None, maxcol=72)
Simple writer class which writes output on the file object passed in as *file*
- or, if *file* is None, on standard output. The output is simply word-wrapped
+ or, if *file* is ``None``, on standard output. The output is simply word-wrapped
to the number of columns specified by *maxcol*. This class is suitable for
reflowing a sequence of paragraphs.