closure_spacing should ignore empty bodies

[bsrz]

Triggering example:

class CustomResponse: Response {
        override init() { } // triggers a warning
}

The expectation would be that empty bodies with a single space does not trigger a warning.

[CookedNick]

I can't think of a single real-world use-case where this would be the case. Please correct me if I'm missing something obvious. Your current example doesn't follow convention as typically you'd write:
class CustomResponse: Response { override init() { super.init() } }

[bsrz]

Well it's not so much about the init, but about the spacing between the brackets. However, when mocking classes for testing, it often happens that you have to implement a method without a body. Using { } (single space) triggers a warning and you have to use two spaces to suppress it like { }.

It's a super big deal, but figured I'd open an issue anyway so it can be reviewed.

[marcelofabri]

Another common case is to make existing types conform to a protocol, for example:

protocol ReusableView: class {
    static var reuseIdentifier: String { get }
}

extension ReusableView where Self: UIView {
    static var reuseIdentifier: String {
        return String(describing: self)
    }
}

extension UITableViewCell: ReusableView { }