THRIFT-2849: spelling errors fixed using codespell tool

Client: All
Patch: Anatol Pomozov

This closes #281
diff --git a/lib/csharp/src/Protocol/TMultiplexedProcessor.cs b/lib/csharp/src/Protocol/TMultiplexedProcessor.cs
index 050b162..35d138c 100644
--- a/lib/csharp/src/Protocol/TMultiplexedProcessor.cs
+++ b/lib/csharp/src/Protocol/TMultiplexedProcessor.cs
@@ -61,7 +61,7 @@
          * Args:
          * - serviceName    Name of a service, has to be identical to the name
          *                  declared in the Thrift IDL, e.g. "WeatherReport".
-         * - processor      Implementation of a service, ususally referred to as "handlers",
+         * - processor      Implementation of a service, usually referred to as "handlers",
          *                  e.g. WeatherReportHandler implementing WeatherReport.Iface.
          */
         public void RegisterProcessor(String serviceName, TProcessor processor)