bpo-38600: NULL -> ``NULL``. (GH-17001)
Also fix some other formatting.
diff --git a/Doc/c-api/init.rst b/Doc/c-api/init.rst
index 61912b9..dc30e49 100644
--- a/Doc/c-api/init.rst
+++ b/Doc/c-api/init.rst
@@ -329,7 +329,7 @@
It overrides :envvar:`PYTHONIOENCODING` values, and allows embedding code
to control IO encoding when the environment variable does not work.
- ``encoding`` and/or ``errors`` may be NULL to use
+ *encoding* and/or *errors* may be ``NULL`` to use
:envvar:`PYTHONIOENCODING` and/or default values (depending on other
settings).