fun addAnnotation(annotationSpec: AnnotationSpec): Builder
Add an annotation to the file.
The annotation must either have a file use-site target
or not have a use-site target specified (in which case it will be changed to file).
fun addAnnotation(annotation: ClassName): Builderfun addAnnotation(annotation: Class<*>): Builderfun addAnnotation(annotation: KClass<*>): Builder