Remove superfluous 'not'

index.html

@@ -859,7 +859,7 @@ <h2><dfn>CaptureController</dfn></h2>
           </pre>
           <div class="issue atrisk">
             <p>
-              {{CaptureController}} does not yet not define any event handlers.
+              {{CaptureController}} does not yet define any event handlers.
               As such, it is not required to inherit from {{EventTarget}}.
               This inheritance was added for the benefit of other specifications
               that extend {{CaptureController}} with event handler attributes.