[docs] Move "| React" to end of OG title

For consistency!

_layouts/default.html

@@ -6,7 +6,7 @@
   <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
   <title>{{ page.title }} | React</title>
   <meta name="viewport" content="width=device-width">
-  <meta property="og:title" content="React | {{ page.title }}">
+  <meta property="og:title" content="{{ page.title }} | React">
   <meta property="og:type" content="website">
   <meta property="og:url" content="http://facebook.github.io/react{{ page.url }}">
   <meta property="og:image" content="http://facebook.github.io/react/img/logo_og.png">