Update win32 build instructions for rst2html

contrib/win32/win32-build.txt

@@ -33,8 +33,8 b' It has the following prerequisites, at l'
   add_path (you need only add_path.exe in the zip file)
       http://www.barisione.org/apps.html#add_path
 
-  Asciidoc - optional
-      http://www.methods.co.nz/asciidoc/
+  Docutils
+      http://docutils.sourceforge.net/
 
 And, of course, Mercurial itself.
 
@@ -79,11 +79,16 b' following files:'
     Microsoft.VC90.MFC.manifest)
 
 Before building the installer, you have to build Mercurial HTML documentation 
-(or fix mercurial.iss to not reference the doc directory). Assuming you have an
-"asciidoc.bat" batch file somewhere in your PATH:
+(or fix mercurial.iss to not reference the doc directory). Docutils does not
+come with a ready-made script for rst2html.py, so you will have to write your
+own and put it in %PATH% like:
+
+  @python c:\pythonXX\scripts\rst2html.py %*
+
+Then build the documentation with:
 
   cd doc
-  mingw32-make ASCIIDOC=asciidoc.bat html
+  mingw32-make RST2HTML=rst2html.bat html
   cd ..
 
 If you use ISTool, you open the C:\hg\hg-release\contrib\win32\mercurial.iss
@@ -102,7 +107,7 b' following:'
   echo compiler=mingw32 >> setup.cfg
   python setup.py py2exe -b 1
   cd doc
-  mingw32-make ASCIIDOC=asciidoc.bat html
+  mingw32-make RST2HTML=rst2html.bat html
   cd ..
   iscc contrib\win32\mercurial.iss