Use at your own risk!!!
Allowing and activating abitrary styles has its danger. The problem is
that Forrest attempts to provide a unified output formats regardless of
the input format. If you use this contract and allow arbitrary styles
through then forrest loose the ability to do this because user can create
"headings" by making text larger and bold, for example. Forrest has no way
of knowing this is supposed to be a heading and therefore cannot render it
as such.
This contract picks up the style element of the input and pass it through
to the output.