[react] inline export syntax

[gilbox]

b more 1337

[justjake]

LGTM, but this may be controversial with the original guide authors? Some people complained about having exports other than at the very bottom of the file.

[ljharb]

In this specific case, I like this change, because 100% of the code below the default export is something that will be moved into inline static properties at some point. In all other cases, I'd want the exports to be the final thing in any file. However, I'm not sure if the inconsistency is clearly explained.

[gilbox]

If the goal is to place all exports at the bottom, then at least one code example needs to be updated.

[goatslacker]

yeah sure

[ljharb]

(I opened #492 to fix that code example)

[justjake]

I'm merging this because I agree and discussion stopped.