add missing return value info for PyDict_DelItem
diff --git a/Doc/api/concrete.tex b/Doc/api/concrete.tex
index 13f1f0a..5c71b3a 100644
--- a/Doc/api/concrete.tex
+++ b/Doc/api/concrete.tex
@@ -1727,7 +1727,7 @@
\begin{cfuncdesc}{int}{PyDict_DelItem}{PyObject *p, PyObject *key}
Removes the entry in dictionary \var{p} with key \var{key}.
\var{key} must be hashable; if it isn't, \exception{TypeError} is
- raised.
+ raised. Returns \code{0} on success or \code{-1} on failure.
\end{cfuncdesc}
\begin{cfuncdesc}{int}{PyDict_DelItemString}{PyObject *p, char *key}