title: How to use Lombok's toBuilder on @SuperBuilder
body: <p>Currently I have these three classes:</p>
  
  <pre><code>@Value
  @NonFinal
  @SuperBuilder
  public class Parent {
      // Some fields
  }
  
  @Value
  @EqualsAndHashCode(callSuper = true)
  @SuperBuilder(toBuilder = true)
  public class ChildA extends Parent {
      // Some fields
  }
  
  @Value
  @EqualsAndHashCode(callSuper = true)
  @SuperBuilder(toBuilder = true)
  public class ChildB extends Parent {
      // Some fields
  }
  </code></pre>
  
  <p>I want to use it in a mapper as follows to avoid duplicating any code:</p>
  
  <pre><code>private ChildA buildChildA(Entity entity) {
      Parent parent = ((ChildB) buildParent(entity, ChildA.builder().build()))
          .toBuilder()
          // Populate Child A fields from entity
          .build();
  }
  
  private ChildB buildChildB(Entity entity) {
      Parent parent = ((ChildA) buildParent(entity, ChildA.builder().build()))
          .toBuilder()
          // Populate Child B fields from entity
          .build();
  }
  
  private Parent buildParent(Partner entity, Parent parent) {
      return parent.toBuilder()
          // Populate Parent fields here
          .build();
  }
  </code></pre>
  
  <p>However when I try to compile I get:</p>
  
  <pre><code>ChildA.java:13: error: method does not override or implement a method from a supertype 
  @SuperBuilder(toBuilder = true) 
  ^ 
  ChildB.java:13: error: method does not override or implement a method from a supertype 
  @SuperBuilder(toBuilder = true) 
  ^ 
  2 errors
  </code></pre>
  
  <p>How do you use toBuilder with @SuperBuilder? I'm using lombok v1.18.4.</p>