added doc preview yml file and eecv page link

Author: rao-shwe

modules/learn/pages/clusters-and-availability/xdcr-overview.adoc

@@ -348,4 +348,6 @@ those buckets cannot participate in a replication topology containing ECCV-enabl
 +
 Couchbase Server does not automatically validate ECCV consistency across clusters.
 If you want to enable ECCV, then before creating or modifying XDCR replications, you must manually verify that ECCV is enabled on all participating buckets.
++
+For more information about ECCV, see xref:learn:clusters-and-availability/xdcr-enable-crossclusterversioning.adoc[XDCR enableCrossClusterVersioning].
 ====

preview/DOC-13689-preview.yml

@@ -0,0 +1,28 @@
+sources:
+    docs-server:
+      branches: DOC_13689_update_xdcr_compatibility_matrix
+    docs-analytics:
+      branches: release/8.0
+    docs-devex:
+      url: https://github.com/couchbaselabs/docs-devex.git
+      branches: master
+      startPaths: docs/
+    couchbase-cli:
+      # url: ../../docs-includes/couchbase-cli
+      url: https://github.com/couchbaselabs/couchbase-cli-doc
+      # branches: HEAD
+      branches: master
+      startPaths: docs/
+    backup:
+      # url: ../../docs-includes/backup
+      url: https://github.com/couchbaselabs/backup-docs.git
+      #branches: HEAD
+      branches: master
+      startPaths: docs/    
+    #analytics:
+    #  url: ../../docs-includes/docs-analytics
+    #  branches: HEAD
+    #cb-swagger:
+    #  url: https://github.com/couchbaselabs/cb-swagger
+    #  branches: release/8.0
+    #  start_path: docs