Add Google Analytics to main Docs

[T9991]

1. Paste this code as high in the of the page as possible:

<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'[https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f)](https://www.googletagmanager.com/gtm.js?id=%27+i+dl;f.parentNode.insertBefore(j,f));
})(window,document,'script','dataLayer','GTM-PKWG7ZFR');</script>
<!-- End Google Tag Manager -->

2. Paste this code immediately after the

<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-PKWG7ZFR"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->