If heading content is in backticks, Maruku on ruby 2.1 renders incorrectly

[somasis]

Example of correct rendering: http://exherbo.org/docs/multibuild.html - easy_multibuild.exlib's TOC entry works just fine, the header looks fine. This is done with Ruby 2.0.

Incorrect rendering: http://dev.exherbo.org/~zlin/www/docs/multibuild.html (disregard the lack of CSS style) - easy_multibuild.exlib's TOC entry anchor link is broken, the header looks fine though