static @Nullable TagNameReference createTagNameReference(XmlElement element, @NotNull ASTNode nameElement, boolean startTagFlag) {
    final XmlExtension extension = XmlExtension.getExtensionByElement(element);
    return extension == null ? null : extension.createTagNameReference(nameElement, startTagFlag);
  }
static @Nullable TagNameReference createTagNameReference(XmlElement element, @NotNull ASTNode nameElement, boolean startTagFlag)