Fix Broken React Examples in Try PureScript

[milesfrain]

@spicydonuts and @ptrfrncsmrph, do either of you have suggestions for how to get the React examples working in the Try PureScript environment?

It's currently having issues finding the container (see dev console):
Broken - ButtonsReactHooks

The Halogen examples work great:
Working - ButtonsHalogenHooks

One workaround is to reuse Halogen's awaitBody in the React example, but it would be better to eliminate that Halogen dependency. Also, react dom complains in the dev console about rendering into the document body.
Working with Halogen's awaitBody

[maddie927]

react demo

react demo (no warning)