nested fenced codeblock don't work

[MonDeveloper]

I'm wondering if there is a way to render a fenced codeblock indented, I'm actually trying the classical 4 spaces before the 3 backtick but it doesn't seem to work, it apply a strage box around any single line.

Thanks ina dvance

[FuyukiSakura]

I have submitted a PR #27 to address this problem. Feel free to check it out.