code: private void addParent(MavenProject project, MavenProjectDirectoryDescriptor projectDescriptor, ScannerContext scannerContext) {
          MavenProject parent = project.getParent();
          if (parent != null) {
              MavenProjectDescriptor parentDescriptor = resolveProject(parent, MavenProjectDescriptor.class, scannerContext);
              projectDescriptor.setParent(parentDescriptor);
          }
      }
docs: Add the relation to the parent project.
  
  @param project
  The project.
  @param projectDescriptor
  The project descriptor.