Say I write some text like this:
```
hello
<eod>
Because I've neglected the closing fence mark, the entire document after that point is marked up within a pre block.
This possibility produces unexpected results: no other block tag (or inline, for that matter) can accidentally alter the rest of the document.
Wouldn't it be possible to say something to the effect of:
- Detect fenced code block
- Continue looking for a matching fence
- If I reach the end of the document, break out, render the text as literal backticks (or something), and continue parsing
