convert_hn isn't being used properly

[derenrich]

it seems you intended to override the convert_hn function in markdownify but that function is actually called _convert_hn (see the source).

So I think that function never actually gets called. And if it were called it would not work properly as it would call a non-existent function.

Changing it to _convert_hn fixes it though I'm not actually sure this patch is needed at all.