Name calculation should take account of CSS block vs inline

[dd8]

Both Firefox and Chrome append extra spaces for block elements embedded in name-from-content elements (which makes sense because the name better matches the visual presentation) but this isn't specified in either accname or html-aam.

Edit: ~~Safari~~ Apple Accessibility Inspector gets quite confused when name-from-content elements contain block elements, but these are voiced as shown below in VoiceOver

<a href="/">One<span>Two</span></a>

AccName: OneTwo (Chrome and FF), One Two (Safari) Visual label: OneTwo

<a href="/">One<p>Two</p></a>

AccName: One Two (Chrome and FF), One Two (Safari) Visual label: One Two

<a href="/">One<span style="display:block">Two</span></a>

AccName: One Two (Chrome and FF), One Two (Safari) Visual label: One Two

[JAWS-test]

Related: https://github.com/w3c/accname/issues/16 and https://github.com/w3c/accname/issues/3

[jnurthen]

also see https://github.com/w3c/aria/issues/699