book: there is no guessing game anymore, so remove references to it

src/doc/trpl/README.md

@@ -11,8 +11,7 @@ navigate through the menu on the left.
 <h2 class="section-header"><a href="basic.html">Basics</a></h2>
 
 This section is a linear introduction to the basic syntax and semantics of
-Rust. It has individual sections on each part of Rust's syntax, and culminates
-in a small project: a guessing game.
+Rust. It has individual sections on each part of Rust's syntax.
 
 After reading "Basics," you will have a good foundation to learn more about
 Rust, and can write very simple programs.

src/doc/trpl/arrays-vectors-and-slices.md

@@ -99,7 +99,5 @@ You can also take a slice of a vector, `String`, or `&str`, because they are
 backed by arrays. Slices have type `&[T]`, which we'll talk about when we cover
 generics.
 
-We have now learned all of the most basic Rust concepts. We're ready to start
-building ourselves a guessing game, we just need to know one last thing: how to
-get input from the keyboard. You can't have a guessing game without the ability
-to guess!
+We have now learned all of the most basic Rust concepts. Next, we learn how to
+get input from the keyboard.

src/doc/trpl/basic.md

@@ -1,8 +1,7 @@
 % Basics
 
 This section is a linear introduction to the basic syntax and semantics of
-Rust. It has individual sections on each part of Rust's syntax, and cumulates
-in a small project: a guessing game.
+Rust. It has individual sections on each part of Rust's syntax.
 
 After reading "Basics," you will have a good foundation to learn more about
 Rust, and can write very simple programs.

src/doc/trpl/compound-data-types.md

@@ -361,5 +361,4 @@ and brittle `if`/`else`s.
 
 [arity]: ./glossary.html#arity
 [match]: ./match.html
-[game]: ./guessing-game.html#comparing-guesses
 [generics]: ./generics.html