Fix grammar in disaster recovery FAQ.

Author: ttorble

articles/site-recovery/site-recovery-faq.yml

@@ -124,7 +124,7 @@ sections:
       - question: |
          Is there a cost associated to perform disaster recovery drills/test failover?
         answer: |
-              There isn't any separate cost for disaster recovery drill. There is compute charges after the virtual machine is created after the test failover.
+              There isn't any separate cost for disaster recovery drill. There are compute charges after the virtual machine is created after the test failover.
 
 
   - name: Security