React-starter-kit: Any Mocha docs need to be erased

[piglovesyou]

From #657 . There is already Jest installed so any docs should not include something about Mocha to avoid confusion.

@langpavel
Documentation indeed needs improvements

There are still article written about Mocha:
https://github.com/kriasoft/react-starter-kit/blob/master/docs/testing-your-application.md#testing-your-application

[langpavel]

Good point. This should be easy PR! :-)

[aguscha333]

I can work on this if it's not taken already 😄

[aguscha333]

Wasn't this done already in #1624?

[piglovesyou]

@aguscha333 Seems you're right. And I found a few more "mocha" descriptions left in docs/getting-started.md. So glad if you would modify that part too.

[aguscha333]

@piglovesyou done, link to the PR #1729

[piglovesyou]

Resolved by #1729 .