.tup files ending in comments without newline cause typeup to freeze indefinitely

This `.tup` file

```
## A Header

Some text

// A comment
```

(no newline at the end) will cause typeup to freeze indefinitely. On my 8-core machine, only one of the cores appear to be used at all, and it's at maximum utilization (by the `node` process), but it's enough for my fan to go crazy...