doc: tweak home page redirect to latest
Try to reduce the page flash when redirecting to latest/index.html
<head>
<title>ACRN Hypervisor documentation</title>
<meta http-equiv="refresh" content="0; URL=latest/index.html">
-<meta name="keywords" content="automatic redirection">
+ <script>
+ window.location.href = "latest/index.html"
+ </script>
</head>
<body>
-Please visit the <a href="/latest/">latest ACRN documentation</a>
+ <p>Please visit the <a href="/latest/">latest ACRN documentation</a></p>
</body>
</html>
