Add proper 4 spaces indentation

Related to https://github.com/briannesbitt/Carbon/pull/165
Thx https://github.com/fabpot/PHP-CS-Fixer
It creates unnecessary noise in changes (PRs, commits) when you have to increase/decrease the alignment due to added or removed lines of different lengths. Especially with long paragraphs like this. 
And the benefit of having it all on the same column is minor.

That's one of the reasons many newer sane coding standards do not use any alignment. And so should this project IMO :)