message: chore(examples): use helper function in overview
diff: import React, { useState } from 'react';
  -import ReactFlow, { removeElements, addEdge, MiniMap, Controls, Background } from 'react-flow-renderer';
  +import ReactFlow, { removeElements, addEdge, MiniMap, Controls, Background, isNode } from 'react-flow-renderer';
  const onNodeDragStart = (node) => console.log('drag start', node);
  const onNodeDragStop = (node) => console.log('drag stop', node);
  -const onElementClick = (element) => console.log('click', element);
  +const onElementClick = (element) => console.log(`${isNode(element) ? 'node' : 'edge'} click:`, element);
  const onSelectionChange = (elements) => console.log('selection change', elements);
  const onLoad = (reactFlowInstance) => {
  console.log('flow loaded:', reactFlowInstance);
  