Add missing \declaremodule for zipfile.
diff --git a/Doc/lib/libzipfile.tex b/Doc/lib/libzipfile.tex
index f29c47f..e8d409b 100644
--- a/Doc/lib/libzipfile.tex
+++ b/Doc/lib/libzipfile.tex
@@ -1,6 +1,7 @@
 \section{\module{zipfile} ---
          Work with ZIP archives}
 
+\declaremodule{standard}{zipfile}
 \modulesynopsis{Read and write ZIP-format archive files.}
 \moduleauthor{James C. Ahlstrom}{jim@interet.com}
 \sectionauthor{James C. Ahlstrom}{jim@interet.com}