fix: rubocop changes

lib/nexus_cqrs/command_executor.rb

 module NexusCqrs
   class CommandExecutor
-
     # @param [NexusCqrs::CommandBus] command_bus
     def initialize(command_bus)
       @bus = command_bus
@@ -27,6 +26,5 @@ module NexusCqrs
       @register_handlers = block
       @register_handlers.call(self)
     end
-
   end
 end