Typo: book the => document the

Author: Havvy

src/introduction.md

@@ -30,7 +30,7 @@ separately by extracting documentation attributes from their source code. Many
 of the features that one might expect to be language features are library
 features in Rust, so what you're looking for may be there, not here.
 
-Similarly, this book does not usually book the specifics of `rustc` as a
+Similarly, this book does not usually document the specifics of `rustc` as a
 tool or of Cargo. `rustc` has its own [book][rustc book]. Cargo has a
 [book][cargo book] that contains a [reference][cargo reference]. There are a few
 pages such as [linkage] that still describe how `rustc` works.