code: def create_configfield_ref_target_node(target_id, env, lineno):
      
      target_node = nodes.target('', '', ids=[target_id])
  
      # Store these task/configurable topic nodes in the environment for later
      # cross referencing.
      if not hasattr(env, 'lsst_configfields'):
          env.lsst_configfields = {}
      env.lsst_configfields[target_id] = {
          'docname': env.docname,
          'lineno': lineno,
          'target': target_node,
      }
  
      return target_node
docs: Create a ``target`` node that marks a configuration field.
  
      Internally, this also adds to the ``lsst_configfields`` attribute of the
      environment that is consumed by `documenteer.sphinxext.lssttasks.
      crossrefs.process_pending_configfield_xref_nodes`.
  
      See also
      --------
      `documenteer.sphinxext.lssttasks.crossrefs.process_pending_configfield_xref_nodes`