revise explanation of returns_unicode to reflect bool values
and to include the default value
diff --git a/Doc/lib/libpyexpat.tex b/Doc/lib/libpyexpat.tex
index 83581ec..a0ea8a1 100644
--- a/Doc/lib/libpyexpat.tex
+++ b/Doc/lib/libpyexpat.tex
@@ -216,9 +216,10 @@
\begin{memberdesc}[xmlparser]{returns_unicode}
If this attribute is set to a non-zero integer, the handler functions
-will be passed Unicode strings. If \member{returns_unicode} is 0,
-8-bit strings containing UTF-8 encoded data will be passed to the
-handlers.
+will be passed Unicode strings. If \member{returns_unicode} is
+\constant{False}, 8-bit strings containing UTF-8 encoded data will be
+passed to the handlers. This is \constant{True} by default when
+Python is built with Unicode support.
\versionchanged[Can be changed at any time to affect the result
type]{1.6}
\end{memberdesc}