Minimally update 2.10.0 release notes wording

Author: vincentkam

Release Notes/Release Notes v2.10.0.md

@@ -18,7 +18,7 @@ Documentation on the .NET driver can be found at:
 
 http://mongodb.github.io/mongo-csharp-driver/
 
-Documentation on the new client-side field level encryption feature can be found:
+Documentation on the new client-side field level encryption feature can be found at:
 
 http://mongodb.github.io/mongo-csharp-driver/2.10/reference/driver/crud/client_side_encryption/