Update tutorial.dox (#246)

remove excess spaces which show up as literal <br> in the docs

docs/tutorial.dox

@@ -203,7 +203,7 @@ disconnect event and must be explicitly reset.
     ...
 @endcode
 
-@section SendingPacket Sending a packet to an ENet peer            
+@section SendingPacket Sending a packet to an ENet peer
 
 Packets in ENet are created with enet_packet_create(), where the size
 of the packet must be specified. Optionally, initial data may be