VNF Validation Documentation broken link fix

Change-Id: Id4a019ddb1781ab38a450caf21a941a183b83f6a
Issue-ID: DOC-650
Signed-off-by: ramagp <ramakrishnagp@aarnanetworks.com>
diff --git a/docs/guides/onap-user/design/pre-onboarding/index.rst b/docs/guides/onap-user/design/pre-onboarding/index.rst
index 43a82fb..07510ef 100644
--- a/docs/guides/onap-user/design/pre-onboarding/index.rst
+++ b/docs/guides/onap-user/design/pre-onboarding/index.rst
@@ -79,7 +79,11 @@
 For Validation of VNF and PNF packages the tools delivered by VNFSDK can be
 used:
 
-`VNF Validation Documentation <../../../onap-provider/vnfvalidator.rst>`_
+.. toctree::
+   :maxdepth: 1
+   :titlesonly:
+
+   ../../../onap-provider/vnfvalidator.rst
 
 Prior to resource onboarding, the Certification Group does the following: