use an existing url for javadoc url

Signed-off-by: olivier lamy <oliver.lamy@gmail.com>

tests/test-webapps/test-proxy-webapp/src/main/webapp/WEB-INF/web.xml

@@ -8,7 +8,7 @@
     <servlet-class>org.eclipse.jetty.proxy.ProxyServlet$Transparent</servlet-class>
     <init-param>
       <param-name>proxyTo</param-name>
-      <param-value>https://www.eclipse.org/jetty/javadoc/</param-value>
+      <param-value>https://www.eclipse.org/jetty/javadoc/jetty-11/index.html?overview-summary.html</param-value>
     </init-param>
     <init-param>
       <param-name>hostHeader</param-name>
@@ -23,4 +23,4 @@
     <url-pattern>/current/*</url-pattern>
   </servlet-mapping>
 
-</web-app>
+</web-app>