code: func (v *Entry) RemoveIcon(iconPos EntryIconPosition) {
  	C.gtk_entry_set_icon_from_icon_name(v.native(),
  		C.GtkEntryIconPosition(iconPos), nil)
  }
docs: // RemoveIcon() is a wrapper around gtk_entry_set_icon_from_icon_name()
  // with a nil pointer to the icon name.