Update SharePointDocumentationToc.xml

Author: davidchesnut

misc/SharePointDocumentationToc.xml

@@ -44,7 +44,7 @@
 			</Item>
 		</Item>
 	</Item>
-	<Item text="Additional SharePoint Resources" url="" SEODescription="">
+	<Item text="Additional SharePoint Resources" url="external" SEODescription="">
 		<Item text="SharePoint Add-ins Docs" url="https://msdn.microsoft.com/en-us/library/office/fp179930.aspx" IsExternal="true" SEODescription="" />
 	</Item>
 </Menu>