remove extraneous 'is'

Author: titusfortner

webdriver-spec.html

@@ -2179,7 +2179,7 @@ <h3>Processing Capabilities</h3>
     or self-signed TLS certificates on <a data-lt=go>navigation</a>.
 
    <dt>"<code>setWindowRect</code>"
-   <dd>Boolean indicating whether the <a>remote end</a> is supports all of the
+   <dd>Boolean indicating whether the <a>remote end</a> supports all of the
     <a>commands</a> in <a href=#h-resizing-and-positioning-windows>Resizing and Positioning Windows</a>.
   </dl>