Fixer to apply indent for multiple line breaks

[brettz9]

The likes of such a block as below is not handled, with the line with the text "new" not getting the indent applied.

This is Markdown.

> This is a nested blockquote.
>
> >   ```js
> >  console.log('Hello, \\
> > new\\
> > world!')
> >  console.log('Hello, \\
> >    world!')
> >   ```