Missing information on removing `Monster`

https://github.com/amethyst/rustrogueliketutorial/blob/33872fe582f226178436847e1f74eafcbf9c0d1a/book/src/chapter_57.md?plain=1#L1509

At this point in the tutorial, `Monster` is still used in `inventory_system`.
From what I see in the code repository, checks on wether the target is a monster or not have been removed silently [here](https://github.com/amethyst/rustrogueliketutorial/blob/33872fe582f226178436847e1f74eafcbf9c0d1a/chapter-57-ai/src/inventory_system.rs#L83-L85) and [here](https://github.com/amethyst/rustrogueliketutorial/blob/33872fe582f226178436847e1f74eafcbf9c0d1a/chapter-57-ai/src/inventory_system.rs#L93-L95).

It should be mentioned in the text of the tutorial before the part about removing `Monster`.
Also, should there be a replacement check here, like testing if the target as some attributes?