update pool docs

satrs-book/README.md

@@ -5,7 +5,14 @@ High-level documentation of the [sat-rs project](https://absatsw.irs.uni-stuttga
 
 ## Building
 
-If you have not done so, install `mdbook` using `cargo install mdbook --locked`.
+If you have not done so, install the pre-requisites first:
+
+```sh
+cargo install mdbook --locked
+cargo install mdbook-linkcheck --locked
+```
+
+After that, you can build the book with:
 
 ```sh
 mdbook build