Update cpptutorial.md

Fixed incorrect description on client side streaming.

cpp/cpptutorial.md

@@ -60,7 +60,7 @@ Then you define `rpc` methods inside your service definition, specifying their r
   rpc ListFeatures(Rectangle) returns (stream Feature) {}
 ```
 
-- A *client-side streaming RPC* where the client writes a sequence of messages and sends them to the server, again using a provided stream. Once the client has finished writing the messages, it waits for the server to read them all and return its response. You specify a server-side streaming method by placing the `stream` keyword before the *request* type.
+- A *client-side streaming RPC* where the client writes a sequence of messages and sends them to the server, again using a provided stream. Once the client has finished writing the messages, it waits for the server to read them all and return its response. You specify a client-side streaming method by placing the `stream` keyword before the *request* type.
 ```
   // Accepts a stream of Points on a route being traversed, returning a
   // RouteSummary when traversal is completed.