Update index.html

Updated pull request with changes to the Measurable Guidance opportunity as a result of the Silver TF discussion 18 February in response to #41
See https://www.w3.org/2022/02/18-silver-minutes.html#ResolutionSummary

requirements/index.html

@@ -113,7 +113,7 @@ <h4>Usability</h4>
 					<h4>Conformance Model</h4>
 					<p>There are several areas for exploration in how conformance can work. These opportunities may or may not be incorporated. Then need to work together, and that interplay will be governed by the design principles</p>
 					<ul>
-						<li><strong>Measurable Guidance</strong>: Certain accessibility guidance is quite clear and measurable. Others, far less so. There are needs of people with disabilities, especially cognitive and low vision disabilities that are not well served by guidance that can only be measured by pass/fail statement. Multiple means of measurement, in addition to pass/fail statements, allow inclusion of more accessibility guidance.</li>
+						<li><strong>Measurable Guidance</strong>: There are needs of people with disabilities, such as cognitive and low vision disabilities that cannot be stated in a single easy-enough-to-measure pass/fail statement. In addition, one area of exploration is to innovate in the area of ways to know whether or not you have followed guidance. By expressing how-to implement and how to measure separately, as well as by allowing multiple means of measurement, we can allow inclusion of more accessibility guidance.</li>
 						<li><strong>Task-Based Assessment</strong>: Moving away from strictly web pages and web sites as a collection of web pages, WCAG 3.0 could set the scope of conformance as a comprehensive set of tasks as defined by the author of the site or application. A properly marked up button doesn't help anything if the user can't complete the task at hand. Task-based assessment allows flexibility for conformance of complex applications that are not conducive to component/tag assessment or full-page assessment.</li>
 						<li><strong>Accessibility Supported</strong>: As the technologies evolve, the interoperability of content, user agents, and assistive technology will continue to blur. Interoperability may be affected by any number of factors outside of the control of the author and publisher of digital content. WCAG 3.0 can include advice to user agents and assistive technology developers. Authors are not responsible for interoperability problems beyond a reasonable effort.</li>
 					</ul>