More updates describing FutureWarnings.
diff --git a/Doc/lib/libexcs.tex b/Doc/lib/libexcs.tex
index ae16082..86b5281 100644
--- a/Doc/lib/libexcs.tex
+++ b/Doc/lib/libexcs.tex
@@ -362,7 +362,7 @@
\setindexsubitem{(built-in warning)}
The following exceptions are used as warning categories; see the
-\module{warnings} module for more information.
+\refmodule{warnings} module for more information.
\begin{excdesc}{Warning}
Base class for warning categories.
@@ -388,6 +388,11 @@
Base class for warnings about dubious runtime behavior.
\end{excdesc}
+\begin{excdesc}{FutureWarning}
+Base class for warnings about constructs that will change semantically
+in the future.
+\end{excdesc}
+
The class hierarchy for built-in exceptions is:
\begin{verbatim}
@@ -431,4 +436,5 @@
+-- SyntaxWarning
+-- OverflowWarning
+-- RuntimeWarning
+ +-- FutureWarning
\end{verbatim}
diff --git a/Doc/lib/libwarnings.tex b/Doc/lib/libwarnings.tex
index b0eb908..48efd68 100644
--- a/Doc/lib/libwarnings.tex
+++ b/Doc/lib/libwarnings.tex
@@ -68,6 +68,9 @@
\lineii{RuntimeWarning}{Base category for warnings about dubious
runtime features.}
+\lineii{FutureWarning}{Base category for warnings about constructs
+that will change semantically in the future.}
+
\end{tableii}
While these are technically built-in exceptions, they are documented