Bugfix: fix accessor for typealias

[aim2120]

Description

Bug

If a class had a typealias with an accessor, this value was not used in the mocks generation. This creates build errors if the typealias is used in APIs that require that level of accessor.

public class MyClass {
  public typealias MyValue = String // <- this typealias would be included in the mock w/o a public accessor
  public func doSomething(with value: MyValue) { }
}

Fix

Add the container's accessibility level to each typealias definition in the template.

Testing

I've added a new class for testing ClassWithTypeAlias that prior to the fix would not create a buildable Swift code.