Update book.tex

AllenDowney · web-flow · commit 9b78593fe930 · 2016-07-22T10:11:07.000-04:00
diff --git a/book/book.tex b/book/book.tex
@@ -9268,7 +9268,7 @@ \section{Debugging}
 
 \item[Format the output:] Formatting debugging output
 can make it easier to spot an error.  We saw an example in
-Section~\ref{factdebug}.  The {\tt pprint} module provides
+Section~\ref{factdebug}.  Another tool you might find useful is the {\tt pprint} module, which provides
 a {\tt pprint} function that displays built-in types in
 a more human-readable format ({\tt pprint} stands for
 ``pretty print'').
