[Feature]: Add support for kramdown block inline attributes lists

[kdomke]

In Kramdown you can add attributes to be used in the rendering process separated by a newline from the paragraph they belong to. Those should not be wrapped around.

Example:

This is some text!
{: class1 }

{: class1 }
This works as well!

is rewrapped to this at the moment:

This is some text!{: class1 }

{: class1 }This works as well!

which does not work anymore.

Documentation:

https://kramdown.gettalong.org/syntax.html#block-ials