Add in rel attribute to general links

git-svn-id: https://svn.apache.org/repos/asf/forrest/trunk@595295 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/main/webapp/resources/schema/dtd/document-v20.mod b/main/webapp/resources/schema/dtd/document-v20.mod
index cd2886b..022ef6e 100644
--- a/main/webapp/resources/schema/dtd/document-v20.mod
+++ b/main/webapp/resources/schema/dtd/document-v20.mod
@@ -115,7 +115,8 @@
         Indicates that the element requires to have hyperlink attributes.
 ==================================================================== -->
 <!ENTITY % link.att 'href      CDATA             #REQUIRED
-                     title     CDATA             #IMPLIED'>
+                     title     CDATA             #IMPLIED
+                     rel       CDATA             #IMPLIED'>
 <!-- =============================================================== -->
 <!-- General definitions -->
 <!-- =============================================================== -->