texi2html: Copy the makeinfo-like footnotestyle from texi2html example

texi2html: Copy the makeinfo-like footnotestyle from texi2html example

texi2html formatted footnotes in an undesirable way, but Patrice imlemented
the same behavior as makeinfo --html in examples/makeinfo.init, so I
simply copied that code from there. If the example file in the texi2html
distribution ever changes, we need to update this code!