bpo-44135: [docs] Fix inline markup (GH-28095)

Fidget-Spinner · web-flow · commit 9a7ec2fcdee2 · 2021-08-31T18:01:17.000+02:00
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
@@ -916,7 +916,7 @@ are always available.  They are listed here in alphabetical order.
    Return ``True`` if *class* is a subclass (direct, indirect, or :term:`virtual
    <abstract base class>`) of *classinfo*.  A
    class is considered a subclass of itself. *classinfo* may be a tuple of class
-   objects or a :ref:`types-union`, in which case return True if *class* is a
+   objects or a :ref:`types-union`, in which case return ``True`` if *class* is a
    subclass of any entry in *classinfo*.  In any other case, a :exc:`TypeError`
    exception is raised.
 
