GitHub Pages emits warning about syntax highlighter

[Matt Brictson]

You are attempting to use the 'pygments' highlighter, which is currently unsupported on GitHub Pages. Your site will use 'rouge' for highlighting instead. To suppress this warning, change the 'highlighter' value to 'rouge' in your '_config.yml'. For more information, see https://help.github.com/articles/page-build-failed-config-file-error/#fixing-highlighting-errors.

[Lee Hambley]

Thanks @mattbrictson