This is the behavior with previous versions of reveal-hugo. Folks
wanting to use Hugo's compile-time highlighter for code blocks should
opt into it by setting `codeFences = true`
Unfortunately the config.toml is shared by all the examples and so we
try to push example-specific config into the index files. With markdown
configuation that's not possible, so the best we can do is tell the user
they need to comment it in to try it out. The better solution in the
future would be to pull this example out into it's own Hugo site.
Now any Hugo section can be configured to generate a presentation without altering its type, and the theme is more easily copied into existing sites without conflicting with any preexisting layouts.
Josh Dzielak