Support #383 - odd feedback when changing an existing, recurring project

- Fixed wording (support issue #383) when modifying a recurring task (thanks
  to T. Charles Yun).

src/command.cpp

@@ -1424,7 +1424,7 @@ int handleModify (std::string &outs)
           std::cout << "Task "
                     << task->id
                     << " is a recurring task, and all other instances of this"
-                    << " task may be modified."
+                    << " task will be modified."
                     << std::endl;
 
         Task before (*other);