Typo fixes

Typos were fixed in bin/md2html.cfg, bin/subst.default.sh,
nojs-menu.html and nojs-menu.md.

The nojs-menu.html now links to bin/index.html and inc/index.html but
the rest of the html files for now do not. It seems like it might be
good if they do, at least bin/index.html, but if that is decided against
this can be rolled back instead.

nojs-menu.md

@@ -29,3 +29,5 @@
 * [IOCCC Security Policy](SECURITY.html)
 * [Thanks for the help](thanks-for-help.html)
 * [IOCCC markdown](markdown.html)
+* [Website scripts](bin/index.html)
+* [Script include files](inc/index.html)