document updates.

JetCore.txt

@@ -213,6 +213,11 @@ used for making comments and is ignored by the jet reader.
 
 The comments tag has no attributes.
 
+\section{cookie}
+
+Use the cookie tag to specify a cookie when using the CGI features
+of JET. 
+
 \section{dump}
 
 Use the dump tag to display the contents of all the global, local and