Update from Issue 44

[alastc]

Closes Issue 44 in WCAG3 repo
Closes #727

All the updates are from comments in Issue 44.

Preview in context from this HTML Diff.

[GreggVan]

under Measurable Guidance

"Mulitple means of measurement" sounds like two ways to measure the same thing. Suggest the following change to fix this but preserve the intended meaning. (Note: assertions are also true/false - there is or isnt an assertion so I changed true/false to "true/false performance or outcome" to make it clear.

change

WCAG 3.0 can include multiple means of measurement, in addition to true/false statements, allowing inclusion of more accessibility guidance.
to
WCAG 3.0 can include guidance (provisions) that use different means of evaluation beyond just true/false performance or outcome statements, allowing the inclusion of more accessibility guidance.

[GreggVan]

One item missing from the new Requirements list is

Self-Validation
The WCAG 3 guidelines document shall meet all of its own requirements (or at least all of them to the XXX level).