Document that heappop() and heapreplace() raise IndexError if the heap
is empty.
diff --git a/Doc/lib/libheapq.tex b/Doc/lib/libheapq.tex
index 38c38d8..38f9b1a 100644
--- a/Doc/lib/libheapq.tex
+++ b/Doc/lib/libheapq.tex
@@ -45,7 +45,7 @@
\begin{funcdesc}{heappop}{heap}
Pop and return the smallest item from the \var{heap}, maintaining the
-heap invariant.
+heap invariant. If the heap is empty, \exception{IndexError} is raised.
\end{funcdesc}
\begin{funcdesc}{heapify}{x}
@@ -55,6 +55,7 @@
\begin{funcdesc}{heapreplace}{heap, item}
Pop and return the smallest item from the \var{heap}, and also push
the new \var{item}. The heap size doesn't change.
+If the heap is empty, \exception{IndexError} is raised.
This is more efficient than \function{heappop()} followed
by \function{heappush()}, and can be more appropriate when using
a fixed-size heap. Note that the value returned may be larger