[c2]: Value attribute should be supported by WYSIWYG editor [finish #74273870] 

A user reported that the "value" attribute is being stripped out by the WYSIWYG editor.  We state that this is supported HTML on the "Supported HTML" page.

For example:
```
<ol>
<li value="100">100</li>
<li>101</li>
</ol>
```

Should be valid HTML that the WYSIWYG respects.

https://console.getsatisfaction.com/getsatisfaction/conversations/extending_supported_html_tags_and_parameters
 https://www.pivotaltracker.com/story/show/74273870