Add an index entry for the discussion of PyEval_CallObject().
This is related to SF bug #485165.
diff --git a/Doc/ext/extending.tex b/Doc/ext/extending.tex
index 22623e9..6cd1137 100644
--- a/Doc/ext/extending.tex
+++ b/Doc/ext/extending.tex
@@ -509,14 +509,15 @@
section~\ref{refcounts}, ``Reference Counts.''
Later, when it is time to call the function, you call the C function
-\cfunction{PyEval_CallObject()}. This function has two arguments, both
-pointers to arbitrary Python objects: the Python function, and the
-argument list. The argument list must always be a tuple object, whose
-length is the number of arguments. To call the Python function with
-no arguments, pass an empty tuple; to call it with one argument, pass
-a singleton tuple. \cfunction{Py_BuildValue()} returns a tuple when its
-format string consists of zero or more format codes between
-parentheses. For example:
+\cfunction{PyEval_CallObject()}.\ttindex{PyEval_CallObject()} This
+function has two arguments, both pointers to arbitrary Python objects:
+the Python function, and the argument list. The argument list must
+always be a tuple object, whose length is the number of arguments. To
+call the Python function with no arguments, pass an empty tuple; to
+call it with one argument, pass a singleton tuple.
+\cfunction{Py_BuildValue()} returns a tuple when its format string
+consists of zero or more format codes between parentheses. For
+example:
\begin{verbatim}
int arg;