Multi-line code block enclosed in backticks doesn't work

Just found this project. Thanks a lot for creating this.

I was trying to use code block with 3 backticks (`\`` ... ```) but it doesn't work.

Input:

	```
	echo "test code"
	```

Output:

```
`<code></code>
echo "test code"
`<code></code>
```

Should output:

```
<code>
echo "test code"
</code>
```