[docs] Update share button (#7097)

_layouts/default.html

@@ -111,7 +111,7 @@
       var js, fjs = d.getElementsByTagName(s)[0];
       if (d.getElementById(id)) return;
       js = d.createElement(s); js.id = id;
-      js.src = "//connect.facebook.net/en_US/all.js#xfbml=1&appId=623268441017527";
+      js.src = "//connect.facebook.net/en_US/sdk.js#xfbml=1&version=v2.6&appId=623268441017527";
       fjs.parentNode.insertBefore(js, fjs);
     }(document, 'script', 'facebook-jssdk'));