Support for typealiases in valid_ibinspectable

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Rule Request

I have a case where I am creating an IBDesignable Map View, where the developer can input individual coordinates as IBInspectable properties. To keep consistent with the CoreLocation API, It would be ideal to have these IBInspectable properties be of type CLLocationDegrees instead of type Double (CLLocationDegrees is a typealias for Double). Because swiftlint doesn't recognize that CLLocationDegrees as a Double, it produces a warning saying it is a declaration violation. I am sure there are numerous other cases where this type of issue could come up.

I am proposing that any new whitelisted types for valid_ibinspectable be opt-in, and configurable in the yaml file as a new type to support for the rule. I think this would be easier to implement than having to have the linter manually cross-reference any types or do any extra work.

Thanks for your consideration.

Start by tracing the valid_ibinspectable rule and how SwiftLint reads YAML configuration. Clarify the opt-in typealias behavior and use the rule's existing test coverage, if available, to verify that configured aliases such as CLLocationDegrees are accepted while unconfigured types retain current behavior.