Make the title and edition consistent.

book.tex

@@ -102,12 +102,12 @@ showstringspaces=false
 
 \frontmatter
 
-\HalfTitle{Essentials of Compilation, Python Edition}
+\HalfTitle{Essentials of Compilation, \python{Python}\racket{Racket} Edition}
 
 
 \halftitlepage
 
-\Title{Essentials of Compilation, Python Edition}
+\Title{Essentials of Compilation, \python{Python}\racket{Racket} Edition}
 
 \Booksubtitle{The Incremental, Nano-Pass Approach}