Illegal offset type in isset or empty

Added missing spot
And spaces for code consistency

@unamatasanatarai I didn't see any reason as to why you didn't change [l.812](https://github.com/unamatasanatarai/Requests/blob/bf64ece6a94035983b74596189e9179323ada833/library/Requests/IRI.php#L812) too.

I hope you can easily merge this with your existing pull-request.