Confusing command format

[TiwKangXu]

The format is shown as sfm INDEX [m/SHORT_FORM] [d/], but essentially the deletion has a "larger priority" than editing short form: when I use command such as sfm 2 d/ m/abc or sfm 2 m/abc d/, the short form is deleted and my edited short form is not updated. It is suggested to separate the deletion of short form into another feature.