Chapter 7 (Section 2.6) - Extra Derive not in source

[In Chapter 7 (Section 2.6) - Player Attacking and killing things](https://bfnightly.bracketproductions.com/rustbook/chapter_7.html#player-attacking-and-killing-things) the component has a derive for `ConvertSaveload`, but it seems to be a legacy element that is not in the final source for the chapter, nor any other reference that I could find.