new backend executable names in 5.18

[mdaines]

> rlgen-ruby     Ruby (new, experimental)

I too would like to see some samples.

When will we see rlgen-javascript? I'm only half kidding, though I
think I see parsing going on in JavaScript sometimes that seems like
maybe it could benefit? Plus, I am leaning toward thinking such a
thing could be useful to me, maybe. Maybe fiddling around with that is
a good leisure-time way to learn about this whole subject and about
how Ragel is implemented...