Problem with ToC and Heading Level 4

[tegedik]

Hi again,

This is about #90. I haven’t used Franklin.jl before but I think this issue is about how it handles heading levels in ToC. If you have a heading level 4 (####), there is a render error with only mintoclevel = 2. So, I set the maxtoclevel = 3. Changing it to maxtoclevel = 4 (with or without mintoclevel) also returns an error. Only chapters 2, 5 and 9 have level-4 headings, hence the errors in these chapters.

I created a fresh website using newsite() and encountered the same problem with heading level-4. So, I think this is a bug in Franklin.jl (or something it uses).

[storopoli]

That's great. I knew it could be a bug in Franklin.jl.
Thanks! Let's merge.