Editorial updates for 1.0

[scottaohara]

• [x] add commits/substantial commits since last wide review section.
• [x] Remove instances of referring to this as a draft document.
• [x] question: add a note about dpub roles being conforming, but that they will likely not be understood in web pages by browsers or AT.
• [x] any additional editorial clarifications that can be made which have not already been brought up in other issues.

[scottaohara]

i will handle the commits/substantial commits section

[stevefaulkner]

hid draft notice https://github.com/w3c/html-aria/commit/043b124baefe0e1086347bdff62be05ae30b6382

[patrickhlauke]

proposed a few changes/tweaks https://github.com/w3c/html-aria/pull/306

[scottaohara]

closing as any additional editorial updates beyond what already have PRs should be small / can wait till the next release.