nested bullets (lists within lists)

Forgive me if this is terrible, I don't know perl.
For my use I want different bullet types to indicate a
new nesting level, not simply continue the current list.
The attach patch works for my needs, I can't say it
does or does not break any other language as I'm using
mostly text, C, and asm as input files.

You can ignore the addition of the (usage) and (samp)
extension to (code/diagram/...).

Thanks for reviewing this patch. Nice tool!
Jeremy