Function attributes are not added to generated methods

Mock for protocol show below will not have closure attributes as specified in function signature.
```
public protocol Provider {
    func open(_ url: URL, completionHandler completion: (@MainActor @Sendable (Bool) -> Void)?)
```

Generated code:
```
open func open(_ url: URL, completionHandler completion: ((Bool) -> Void)?) { ... }
```

SwiftyMocky: 4.2.0
