Update to use the new \csimplemacro macro
diff --git a/Doc/ext/extending.tex b/Doc/ext/extending.tex
index 7eafc05..90385e1 100644
--- a/Doc/ext/extending.tex
+++ b/Doc/ext/extending.tex
@@ -1068,11 +1068,11 @@
interpreter can't get in each other's way, because there is a global
lock protecting Python's entire object space. However, it is possible
to temporarily release this lock using the macro
-\code{Py_BEGIN_ALLOW_THREADS}, and to re-acquire it using
-\code{Py_END_ALLOW_THREADS}. This is common around blocking I/O
-calls, to let other threads use the processor while waiting for the I/O to
-complete. Obviously, the following function has the same problem as
-the previous one:
+\csimplemacro{Py_BEGIN_ALLOW_THREADS}, and to re-acquire it using
+\csimplemacro{Py_END_ALLOW_THREADS}. This is common around blocking
+I/O calls, to let other threads use the processor while waiting for
+the I/O to complete. Obviously, the following function has the same
+problem as the previous one:
\begin{verbatim}
bug(PyObject *list) {