Can't mix Markdown and HTML

[Didayolo]

Previously, HTML was not interpreted for the documentation pages of benchmarks:

• HTML not interpreted #836

Now, it works when having Markdown only, and when having HTML only. However, using HTML inside Markdown files break the display.

It is due to the way HTML is detected in this file:

https://github.com/codalab/codabench/blob/develop/src/static/riot/competitions/detail/_tabs.tag

        self.isHTML = function (page_content) {
            return /<(?=.*? .*?\/ ?>|br|hr|input|!--|wbr)[a-z]+.*?>|<([a-z]+).*?<\/\1>/i.test(page_content);
        }