Improved Syntax Highlighter

[ntotten]

I would like to see a few features in our syntax highlighter

1. Icon/text label indicating the language of the code snippet.
2. A way to indicate the file name
3. Ability to highlight lines as added or removed (red/green)
4. Copy button

The emberjs docs have a good example showing 1-3: https://guides.emberjs.com/v2.5.0/getting-started/quick-start/