docs: public static String getTofuExtensionImport(FieldDescriptor desc) {
      // This is run by GenerateParseInfoVisitor, which doesn't necessarily have a classpath
      // dependency on the proto, just a data dependency on the descriptor.
  
      String extensionFieldName = JavaQualifiedNames.getFieldName(desc, false);
  
      String extensionFieldHolderClassName;
      if (desc.getExtensionScope() != null) {
        extensionFieldHolderClassName = JavaQualifiedNames.getQualifiedName(desc.getExtensionScope());
      } else {
        // else we have a 'top level extension'
        extensionFieldHolderClassName =
            JavaQualifiedNames.getPackage(desc.getFile())
                + "."
                + JavaQualifiedNames.getOuterClassname(desc.getFile());
      }
      return extensionFieldHolderClassName + "." + extensionFieldName + ".getDescriptor()";
    }