Please update README

Hello,

thanks a lot for maintaining this language support!

I went through the README today as I was experimenting with this library.

I found 2 places that need to be updated:
- Should step 6 (as well as the code snippet) refer to `highlight.min.js` instead of `highlight.pack.js` ?
- In the code snippet `initHighlightingOnLoad` should be replaced with `highlightAll`
Seeing this deprecation msg:
```
Deprecated as of 10.6.0. initHighlightingOnLoad() deprecated. Use highlightAll() now.
```

I'll be happy to submit a PR if I get permissions for that.

Cheers,
Marianna

Start in the README and locate step 6 and its code snippet. Replace references to highlight.pack.js with highlight.min.js and initHighlightingOnLoad with highlightAll; done means the README no longer recommends the deprecated API or outdated filename.

Written by the indexing model from the issue text.