add explanation of the conclusion block

Author: jsiek

book.tex

@@ -26,7 +26,7 @@
 
 \def\racketEd{0}
 \def\pythonEd{1}
-\def\edition{1}
+\def\edition{0}
 
 % material that is specific to the Racket edition of the book
 \newcommand{\racket}[1]{{\if\edition\racketEd{#1}\fi}}
@@ -3866,12 +3866,17 @@ \section{Select Instructions}
 \fi}  
 
 {\if\edition\racketEd
+%
 There are two cases for the $\Tail$ nonterminal: \key{Return} and
 \key{Seq}. Regarding \key{Return}, we recommend treating it as an
-assignment to the \key{rax} register followed by a jump to the
-conclusion of the program (so the conclusion needs to be labeled).
+assignment to the \key{rax} register followed by a jump to
+the label \key{conclusion}. Later, in Section~\ref{sec:print-x86},
+we discuss the generation of the \key{conclusion} block.
+In the meantime, the interpreter for \LangXVar{} recognizes a jump
+to \key{conclusion} as the end of the program.
 For $\SEQ{s}{t}$, you can translate the statement $s$ and tail $t$
 recursively and then append the resulting instructions.
+%
 \fi}
 
 {\if\edition\pythonEd\pythonColor