typo fix

Author: scottaohara

tests/summary-allowances.html

@@ -122,7 +122,7 @@ <h3>Test 3</h3>
 				</div>
 
         <div class="testcase">
-					<p>AUsing an aria-haspopup attribute is allowed</p>
+					<p>Using an aria-haspopup attribute is allowed</p>
           <details open>
             <summary aria-haspopup=true>test 2</summary>
             has aria-haspopup=true attribute