added documentation about sexp

doc/lib.txt

@@ -325,6 +325,10 @@ Parsers
 * `rstgen <rstgen.html>`_
   This module implements a generator of HTML/Latex from reStructuredText.
 
+* `sexp <sexp.html>`_
+  High performance sexp parser and generator, mainly for communication
+  with emacs.
+
 
 XML Processing
 --------------

web/news.txt

@@ -223,6 +223,7 @@ Library additions
   space between ``.. <`` and ``.. ^`` is not necessary anymore.
 - Added ``system.xlen`` for strings and sequences to get back the old ``len``
   operation that doesn't check for ``nil`` for efficiency.
+- Added sexp.nim to parse and generate sexp.
 
 
 Bugfixes