docs: def process_pending_configfield_xref_nodes(app, doctree, fromdocname):
      """Process the ``pending_configfield_xref`` nodes during the
      ``doctree-resolved`` event to insert links to the locations of
      configuration field nodes.
  
      See also
      --------
      `format_configfield_id`
      `configfield_ref_role`
      `pending_configfield_xref`
      """
      logger = getLogger(__name__)
      env = app.builder.env
  
      for node in doctree.traverse(pending_configfield_xref):
          content = []
  
          # The source is the text the user entered into the role, which is
          # the importable name of the config class's and the attribute
          role_parts = split_role_content(node.rawsource)
          namespace_components = role_parts['ref'].split('.')
          field_name = namespace_components[-1]
          class_namespace = namespace_components[:-1]
          configfield_id = format_configfield_id(class_namespace, field_name)
          if role_parts['display']:
              # user's custom display text
              display_text = role_parts['display']
          elif role_parts['last_component']:
              # just the name of the class
              display_text = role_parts['ref'].split('.')[-1]
          else:
              display_text = role_parts['ref']
          link_label = nodes.literal()
          link_label += nodes.Text(display_text, display_text)
  
          if hasattr(env, 'lsst_configfields') \
                  and configfield_id in env.lsst_configfields:
              # A config field topic is available
              configfield_data = env.lsst_configfields[configfield_id]
  
              ref_node = nodes.reference('', '')
              ref_node['refdocname'] = configfield_data['docname']
              ref_node['refuri'] = app.builder.get_relative_uri(
                  fromdocname, configfield_data['docname'])
              ref_node['refuri'] += '#' + configfield_id
  
              ref_node += link_label
  
              content.append(ref_node)
  
          else:
              # Fallback if the config field isn't known. Just print the Config
              # field attribute name
              literal_node = nodes.literal()
              link_label = nodes.Text(field_name, field_name)
              literal_node += link_label
  
              content.append(literal_node)
  
              message = 'lsst-config-field could not find a reference to %s'
              logger.warning(message, role_parts['ref'], location=node)
  
          # replacing the pending_configfield_xref node with this reference
          node.replace_self(content)