fix \NULL with following space and no {}
diff --git a/Doc/api/init.tex b/Doc/api/init.tex
index c3c7a1a..6d009bb 100644
--- a/Doc/api/init.tex
+++ b/Doc/api/init.tex
@@ -682,7 +682,7 @@
If this function returns \NULL, no exception has been raised and the
caller should assume no current thread state is available.
\versionchanged[Previously this could only be called when a current
- thread is active, and \NULL meant that an exception was raised]{2.3}
+ thread is active, and \NULL{} meant that an exception was raised]{2.3}
\end{cfuncdesc}
\begin{cfuncdesc}{int}{PyThreadState_SetAsyncExc}{long id, PyObject *exc}