This needs some further investigation. This would produce code such as the following AFAICS:
```
div
div
| Hello
```
->
```
<div>
<div>
Hello
```
So "Hello" would now be nested inside two `<div>` tags that are not properly terminated.

I think we rather need to find out why the `input` tag isn't considered singular. (and finally adjust the list of singular tags according to the doctype used)