Doc: fix search box. Feel very grateful for Python.

Doc: fix search box.  Feel very grateful for Python.

Remember why we banned perl [apart from the fact that is parses (and
thus can crash on) comments].  It took me more than an hour to
translate

    '<li>' + open ('file').read ()

to seven lines of perl before it worked, including two magic
variables, with several solutions failing silently.  Ugh.