`<h-line>` stops all further output

Unless I'm missing something, `<h-line`> seems completely broken and skips what comes after the tag (1.4.2):

```
Hello
<h-line/>
World
<h-line/>
!
```

Gets converted to:
```
Hello
<table class="h-line"><tr><th>&nbsp;</th></tr></table>
```

Note that "World", "!", or the second `<h-line>` don't seem to appear.

Also, extra attributes are dropped.