someone accidentally a word

Author: mharen

source/administration/replica-sets.txt

@@ -259,7 +259,7 @@ Arbiters
 
 Arbiters are special :program:`mongod` instances that do not hold a
 copy of the data and thus cannot become primary. Arbiters exist solely
-participate in :ref:`elections <replica-set-elections>`.
+to participate in :ref:`elections <replica-set-elections>`.
 
 .. note::