Remove blank line when a list is before a heading (MyBB)

This is mostly a problem with the CSS of the forum. This will make it look properly.

Problem:

```ini
[h1]Header 1[/h1]

[list]
[*] Item 1
[/list]
```

How it should look:

```ini
[h1]Header1[/h1]
[list]
[*] Item 1
[/list]
```