Remove redundant word "Rules" (#4251)

https://www.w3.org/WAI/WCAG22/Understanding/understanding-act-rules#test-rules-rules-are-informative

Co-authored-by: Mike Gower <[email protected]>

Author: momdo

understanding/understanding-act-rules.html

@@ -11,7 +11,7 @@ <h1>Understanding Test Rules for WCAG 2 Success Criteria</h1>
 		<p><a href="conformance">Understanding Conformance</a> provides related information, including on <a href="conformance#accessibility-support">understanding accessibility support</a>.</p>
 
 		<section>
-			<h2>Test Rules Rules are Informative</h2>
+			<h2>Test Rules are Informative</h2>
 			<p><em>Test Rules are informative — that means they are not required for determining conformance. The basis for determining conformance to WCAG 2 are the success criteria from the WCAG 2 standard — not the Test Rules.</em></p>
 			<p>While W3C's <a href="https://www.w3.org/WAI/standards-guidelines/act/rules/">List of Test Rules for WCAG 2</a> are reviewed by the W3C Accessibility Guidelines Working Group (AGWG), they are not vetted to the same degree as the W3C Web Content Accessibility Guidelines (WCAG) standard (called <em>W3C Recommendation</em>). The WCAG 2 standard is the normative reference on determining conformance.</p>
 		</section>