Add instructions for HTM generation.

README.txt

@@ -21,3 +21,14 @@ format.
 For processing reStructuredText format PEPs, you need the docutils
 package, which is available from PyPI (http://pypi.python.org).
 If you have pip, "pip install docutils" should install it.
+
+
+Generating HTML
+===============
+
+Do not commit changes with bad formatting.  To check the formatting of
+a PEP, use the Makefile.  In particular, to generate HTML for PEP 999,
+your source code should be in pep-0999.txt and the HTML will be
+generated to pep-0999.html by the command "make pep-0999.html".  The
+default Make target generates HTML for all PEPs.  If you don't have
+Make, use the pep2html.py script.