update html attribute list w/ accessibility attrs

added `title` text, `alt` text, `aria-*` (e.g. `aria-hidden`), and `role` attributes.

NOTE: `title` should always be after `href`, and `alt` should be after `src` (e.g. in an `<img>`). I've found that the last two attributes are usually added on the end if necessary (e.g. if the element isn't semantically correct or something needs to be hidden on screen readers).