Fixed doc to including react-dom inner packages

[gilamran]

No description provided.

[blainekasten]

I'm going to cc @tylercollier who worked on #340 to see if someone can confirm these are necessary. Seems curious that they weren't added originally if they are needed.

[jackfranklin]

I made the change that added the Webpack 2 specific docs recently - @gilamran out of interest what version of React are you using? This might be something that's caused by the newest version - we use Webpack + Enzyme + React in our tests and haven't hit upon this problem but we're not quite on the very latest React yet.

[tylercollier]

I'm sorry @blainekasten, I don't know. I attempted to help with #340 because I figured the documentation was lagging and the airbnb/enzyme might benefit from a prompt, and this was confirmed when Leland Richardson said "We added react 15 support, but didn't really update the documentation". Unfortunately, even with my research for my comment in #47, I didn't receive any upvotes which to me tells me I didn't really get to the bottom of things enough to help people.

I agree with your assessment:

Seems curious that they weren't added originally if they are needed.

but then again, I think this happens all the time. Documentation usually gets updated late, etc. Webpack is hard to configure. Understanding the circumstances/dependencies of random projects on the internet and github issues is tough. So what I'm saying here is that while I attempted to help earlier, I probably unfortunately added to the confusion instead, so I'll recommend someone with a better understanding of webpack and enzyme step in.

[ljharb]

I don't think this is relevant any more now that we're on v3.