[FLINK-17675][docs] Update jquery dependency to 3.5.1

This closes apache#12229

NOTICE

@@ -4,6 +4,12 @@ Copyright 2014-2020 The Apache Software Foundation
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
 
+This project bundles the following dependencies under the MIT license.
+See bundled license files for details.
+
+- jQuery v3.5.1 | (c) JS Foundation and other contributors
+	-> in "docs/page/js/jquery.min.js"
+
 This project bundles the following dependencies under the BSD license.
 See bundled license files for details.
 

docs/page/js/flink.js

@@ -123,5 +123,5 @@ $(function() {
 
   // Scroll now too in case we had opened the page on a hash, but wait a bit because some browsers
   // will try to do *their* initial scroll after running the onReady handler.
-  $(window).load(function() { setTimeout(function() { maybeScrollToHash(); }, 25); }); 
+  $(window).ready(function() { setTimeout(function() { maybeScrollToHash(); }, 25); }); 
 });