Add note about the version in which GetoptError was added -- this can
bite people interested in 1.5.2 compatibility.
diff --git a/Doc/lib/libgetopt.tex b/Doc/lib/libgetopt.tex
index c96c3cf..fff3043 100644
--- a/Doc/lib/libgetopt.tex
+++ b/Doc/lib/libgetopt.tex
@@ -64,6 +64,9 @@
attributes \member{msg} and \member{opt} give the error message and
related option; if there is no specific option to which the exception
relates, \member{opt} is an empty string.
+
+\versionchanged[Introduced \exception{GetoptError} as a synonym for
+ \exception{error}]{1.6}
\end{excdesc}
\begin{excdesc}{error}