AsciiDoc titles in the semantic HTML 5 converter

[redbow-kimee]

Titles seems to be a cross cutting confusion for how to be implemented in the semantic HTML 5 converter. Many features have used <strong class="title"> for the title, but it isn't quite perfect in some situations, so I figured I'd mainly link to a few discussions about titles so we can centralize some of the discussion and make things perhaps a bit more uniform.

• Paragraphs: <strong class="title"> is used inline at the beginning of a title as what would be conventionally called a "run-in heading", so having the title inline appears to be the correct thing to do (although, I believe that differs from the current asciidoctor behavior).
• Lists: <ul>\n<strong class="title">Title</strong><li>.... The <strong> kinda/sorta gets promoted to a block element, which might be weird, but it appears to work in all the browsers I've tried.
• Sidebars: Title should probably be a block element, so I made it <p><strong class="title">Title.... This poses issues with following content sometimes being outside of a <p> (if that is indeed an issue).

Anyways, those are a few spots where I've seen title behavior come up. Feel free to link more.

Also this should be tagged with area/html-next, but I haven't got permission.

[redbow-kimee]

https://developer.mozilla.org/en-US/docs/Web/HTML/Element/header