a few typographical changes (e.g. -- => ---) and lots of new stuff in the WWW chapter
diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex
index 1c4e90d..7628a10 100644
--- a/Doc/lib/libstring.tex
+++ b/Doc/lib/libstring.tex
@@ -23,7 +23,7 @@
 \begin{datadesc}{lowercase}
   A string containing all the characters that are considered lowercase
   letters.  On most systems this is the string
-  \code{'abcdefghijklmnopqrstuvwxyz'}.  Do not change its definition --
+  \code{'abcdefghijklmnopqrstuvwxyz'}.  Do not change its definition ---
   the effect on the routines \code{upper} and \code{swapcase} is
   undefined.
 \end{datadesc}
@@ -35,7 +35,7 @@
 \begin{datadesc}{uppercase}
   A string containing all the characters that are considered uppercase
   letters.  On most systems this is the string
-  \code{'ABCDEFGHIJKLMNOPQRSTUVWXYZ'}.  Do not change its definition --
+  \code{'ABCDEFGHIJKLMNOPQRSTUVWXYZ'}.  Do not change its definition ---
   the effect on the routines \code{lower} and \code{swapcase} is
   undefined.
 \end{datadesc}
@@ -43,7 +43,7 @@
 \begin{datadesc}{whitespace}
   A string containing all characters that are considered whitespace.
   On most systems this includes the characters space, tab, linefeed,
-  return, formfeed, and vertical tab.  Do not change its definition --
+  return, formfeed, and vertical tab.  Do not change its definition ---
   the effect on the routines \code{strip} and \code{split} is
   undefined.
 \end{datadesc}