8th column of paragraph inside nested lists becomes code block.

Input:

``` markdown
-   a

    -   b

        c
```

`c` is a code block, when it should be a regular paragraph.

Only happens at the 8th column, e.g., the following is fine:

``` markdown
- a

  - b

    c
```

but the problem comes back if we keep adding levels: `e` will be code:

```
- a

  - b

    - c

      - d

        e
```
