Bug #1541682: Fix example in the "Refcount details" API docs.
Additionally, remove a faulty example showing PySequence_SetItem applied
to a newly created list object and add notes that this isn't a good idea.
diff --git a/Doc/api/concrete.tex b/Doc/api/concrete.tex
index 91fd3bb..3a31287 100644
--- a/Doc/api/concrete.tex
+++ b/Doc/api/concrete.tex
@@ -1840,6 +1840,11 @@
\begin{cfuncdesc}{PyObject*}{PyList_New}{Py_ssize_t len}
Return a new list of length \var{len} on success, or \NULL{} on
failure.
+ \note{If \var{length} is greater than zero, the returned list object's
+ items are set to \code{NULL}. Thus you cannot use abstract
+ API functions such as \cfunction{PySequence_SetItem()} on it
+ or expose it to Python code before setting all items to a
+ real object with \cfunction{PyList_SetItem()}.}
\end{cfuncdesc}
\begin{cfuncdesc}{Py_ssize_t}{PyList_Size}{PyObject *list}