Ch 2, 9, 22 - dead links (Book of Specs)

[NielsRenard]

Hi there, still very much enjoying the tutorial!

I noticed some links to the (slide-rs) specs website are broken:

https://github.com/thebracket/rustrogueliketutorial/blob/master/book/src/chapter_2.md
You can learn more about these stores in The Specs Book.

https://github.com/thebracket/rustrogueliketutorial/blob/master/book/src/chapter_3.md
You can learn more about this in the Specs Book.

https://github.com/thebracket/rustrogueliketutorial/blob/master/book/src/chapter_9.md
"We referenced the Book of Specs for how to do this!"

https://github.com/thebracket/rustrogueliketutorial/blob/master/book/src/chapter_22.md
The Specs Book provides a great clue as to how to exclude a component from a join, so we do that (in main.rs)

[NielsRenard]

PR ready #66

[NielsRenard]

For the chapter 9 specs link: maybe you want to link directly to the "Sort entities based on component value" anchor instead of to the toplevel page, i.e.:
https://specs.amethyst.rs/docs/tutorials/11_advanced_component.html#sorting-entities-based-on-component-value instead of https://specs.amethyst.rs/docs/tutorials/11_advanced_component.html