minor: clarification that hidden members vote

Author: Sam Kleinman

source/core/replication.txt

@@ -93,7 +93,9 @@ Hidden
 
 Hidden members are part of a replica set, but are unable to become
 primary (i.e. have :ref:`priority <replica-set-node-priority>` set to
-a value of ``0``, ) and invisible to client applications.
+a value of ``0``, ) and invisible to client applications. *However,*
+hidden members **do** vote in :ref:`elections
+<replica-set-elections>`.
 
 Hidden members are ideal for instances that will have significantly
 different usage patterns than the other nodes and require separation