More updates describing FutureWarnings.
diff --git a/Doc/doc/doc.tex b/Doc/doc/doc.tex
index 4fec4a3..8c5f338 100644
--- a/Doc/doc/doc.tex
+++ b/Doc/doc/doc.tex
@@ -1306,6 +1306,9 @@
           features.}
   \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}
 \end{verbatim}