SF patch 664183 and SF bug 664044:  Note that both  u'%s' % 'x'  and
'%s' % u'x'  return a unicode object.
diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index a377426..5f4a154 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -834,7 +834,7 @@
   \lineiii{r}{String (converts any python object using
               \function{repr()}).}{(3)}
   \lineiii{s}{String (converts any python object using
-              \function{str()}).}{}
+              \function{str()}).}{(4)}
   \lineiii{\%}{No argument is converted, results in a \character{\%}
                character in the result.}{}
 \end{tableiii}
@@ -855,6 +855,9 @@
     not already a zero.
   \item[(3)]
     The \code{\%r} conversion was added in Python 2.0.
+  \item[(4)]
+    If the object or format provided is a \class{unicode} string,
+    the resulting string will also be \class{unicode}.
 \end{description}
 
 % XXX Examples?