Working on standardizing the doc format for HTML elements

Based on the last month of poking around WPD, I'm noticed a lot of
inconsistency with the HTML element docs.

As far as I know, html elements haven't been worked on much yet so I'll
take the lead on standardizing how an ideal html element article should be
structured.

I'll document this by either editing or augmenting this wiki page:
http://docs.webplatform.org/wiki/WPD:Creating_API_pages

Pearl