Code blocks (```) cannot have empty lines

[madskristensen]

A <code> block is not created when having empty lines like so:

test: {

}

Where as using the tilde characters works fine:

test: {

}

[dprothero]

Confirmed this issue. In addition, you cannot add a class name after the tilde characters as per https://michelf.ca/projects/php-markdown/extra/#fenced-code-blocks

[FransBouma]

When I add a CRLF after 'line 3' in the Fenced code blocks alt txt file for the ExtraMode tests, it works OK (the extra line is inserted properly). Also if I add your test snippet it works fine, (both to txt and html test of course).

Not sure if this project is still alive. I've forked it to add github style code blocks (language specification) and I can't reproduce it with my fork (which is on par with this repo, for ExtraMode).