Fixed broken link to markdown options doc
@@ -175,7 +175,7 @@ We use [marked](https://github.com/chjj/marked) to parse Markdown. To customise
```javascript
Reveal.initialize({
// Options which are passed into marked
- // See https://github.com/chjj/marked#options-1
+ // See https://marked.js.org/#/USING_ADVANCED.md#options
markdown: {
smartypants: true
}