Document PySequence_Size(), and describe PySequence_Length() as simply an
alternate name for the same function.
diff --git a/Doc/api/api.tex b/Doc/api/api.tex
index dfeb060..22d0d4b 100644
--- a/Doc/api/api.tex
+++ b/Doc/api/api.tex
@@ -1876,13 +1876,17 @@
 \code{0} otherwise.  This function always succeeds.
 \end{cfuncdesc}
 
-\begin{cfuncdesc}{int}{PySequence_Length}{PyObject *o}
+\begin{cfuncdesc}{int}{PySequence_Size}{PyObject *o}
 Returns the number of objects in sequence \var{o} on success, and
 \code{-1} on failure.  For objects that do not provide sequence
 protocol, this is equivalent to the Python expression
 \samp{len(\var{o})}.\bifuncindex{len}
 \end{cfuncdesc}
 
+\begin{cfuncdesc}{int}{PySequence_Length}{PyObject *o}
+Alternate name for \cfunction{PySequence_Size()}.
+\end{cfuncdesc}
+
 \begin{cfuncdesc}{PyObject*}{PySequence_Concat}{PyObject *o1, PyObject *o2}
 Return the concatenation of \var{o1} and \var{o2} on success, and \NULL{} on
 failure.   This is the equivalent of the Python