False positive `react/no-unescaped-entities` on whitespace with newlines inside JSX.

[sompylasar]

What version of TypeScript are you using?
2.3.2

What version of typescript-eslint-parser are you using?
3.0.0

What code were you trying to parse?
Code is closed-source, but the gist is this:

<SomeComponent>
  {children}
</SomeComponent>

What did you expect to happen?
No react/no-unescaped-entities warning.

What happened?
False positive react/no-unescaped-entities on whitespace with newlines inside JSX.
https://github.com/yannickcr/eslint-plugin-react/blob/f0dcaca92418bb791f585e867d720a96dd43a277/lib/rules/no-unescaped-entities.js#L72

The code gets parsed as:

JSXElement: '<SomeComponent>'
  Literal: '\n  '
    ...

and react/no-unescaped-entities tells me to escape something there, likely the newline character.
After converting the code to:

<SomeComponent>{children}</SomeComponent>

the warning goes away.

Originally submitted here: #266 (comment)

[sompylasar]

Refs #277

[soda0289]

Thanks.