~~ lineWidth: 40, headingKind: setext ~~
!! should format the headers !!
# H1

## H2

### H3

#### H4

First Header
============

Second Header
-------------

[expect]
H1
==

H2
--

### H3

#### H4

First Header
============

Second Header
-------------

!! should handle level 2 multi-line heading !!
This Header
spans
multiple lines
----------------------------------------


[expect]
This Header
spans
multiple lines
--------------

!! should handle level 1 multi-line heading !!
This Header
spans
multiple lines
========================================


[expect]
This Header
spans
multiple lines
==============
