docs.flutter.io difficult to use on mobile

[sethladd]

From @goderbauer

Just visited docs.flutter.io on my iPhone (Safari on iOS 10) to quickly look up an API. It is very difficult to use on mobile:

• there is no search field to quickly search for something (<--- main problem)
• the actual information is embedded in a strangely scrolling div
• vertical scrolling is enabled even though there is no need for it
• when scrolling through the hamburger menu, the page below it scrolls as well when the end of the hamburger menu is reached.

[jcollins-g]

#1348 is related

[jcollins-g]

flutter/flutter#19987 is related