Fix jsx-key can't detect error in parenthesized expression

[lukyth]

Fix #187

The current implementation miss the case where an arrow function returns (); i.e.

[3, 4, 5].map(x => (<App />));
[3, 4, 5].map(x => (<App>app</App>));

It should be the following code instead.

[3, 4, 5].map(x => (<App key={x} />));
[3, 4, 5].map(x => (<App key={x}>app</App>));

[palantirtech]

Thanks for your interest in palantir/tslint-react, @lukyth! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[jasongornall]

Could really use this!!

[lukyth]

Anything I can do to get this merged?

[adidahiya]

nice, thanks @lukyth!