sphinx_local replica-set-secondary page

Author: Kay Kim

config/sphinx_local.yaml

@@ -46,6 +46,7 @@ theme:
     - /core/replica-set-architectures
     - /core/replica-set-high-availability
     - /core/replica-set-members
+    - /core/replica-set-secondary
     - /core/transactions
     - /geospatial-queries
     - /replication