Rewriting header levels

[BrekiTomasson]

Assuming you've got your # Introduction down already, and you're down in ## Theory or something, then you include a file that contains a # Supposition, then the resulting output would have a H1 nested under a H2.

Would it be possible to rewrite the header levels (via a config flag, most likely) to be additive? So that any header that is imported is just added to the current header level? In that case, since we were at H2 when we included a file, then the H1 in that file would be parsed as an H3 instead.

[camelaissani]

I'm not sure the header level should be driven by this plugin. This plugin objective is to include markdown files and not to deal with the markdown syntax itself.
That said, if someone find a quick win to do that, I will happily merge it.