Non-HTML5 element

[jemrobinson]

What do we want to do with elements like <marquee> or <blink> which are not part of the HTML5 specification?

Decision

We will unwrap these elements to preserve their content. Note that we cannot tell if an unknown element will be treated as a block or inline element by the browser. Therefore we risk merging two blocks of text that would be rendered as separate visual "paragraphs" into a single visual "paragraph". After discussions with Rebekah, we have decided this is acceptable. Implemented in PR #28

We will look to explicitly define parsing behaviour for "knowable" pre HTML5 tags in future releases to minimise the risk of treating a "knowable" block level element as inline - see issue #33.