This is a markdown extension that lets users add a filename and numbering to fenced code blocks in addition to the language.

intended syntax:

```python number=30 path="example-code.py" hl_lines="1 3"
def shrubbery(herring):
    foo = 5
    bar = 9
    return herring.eggs
```

Which will produce html that looks like

<pre><code class="python" data-hl_lines="1 3" data-number="30" data-path="example-code.py">
def foo():
    bar = 4
    return 8
</code></pre>