Mardown Inline HTML not working in Wiki

Created by: fspreiss

1. Summary: The use of raw HTML in Markdown does not work (in the Wiki). This issue was observed in version 6.8.1.

2. Steps to reproduce: Create/edit a Wiki page and enter some raw/inline HTML, such as the definition lists described in the Markdown documentation at github.com or gitlab.com:

   <dl>
    <dt>Definition list</dt>
    <dd>Is something people use sometimes.</dd>
   
    <dt>Markdown in HTML</dt>
    <dd>Does *not* work **very** well. Use HTML <em>tags</em>.</dd>
   </dl>

   The same problem occurs when using other HTML tags such as a

   tags.

   Expected behavior: The HTML is rendered correctly as seen in the Markdown documentation at github.com and in the following image:

   Observed behavior: The output is rendered incorrectly as seen in the Markdown documentation at gitlab.com and in the following image: