feat: callback function add this point to graph

[Aarebecca]

• Options 回调函数添加 this 指向为 Graph

目前添加 this 指向的函数：元素样式映射、交互、插件、数据转换

const graph = new Graph({
  // ...
  node: {
    style: {
      fill: function () {
        // this => graph
        return 'blue';
      },
    },
    state: {
      selected: function () {
        // this => graph
        return {
          fill: 'red',
        };
      },
      activated: {
        fill: function () {
          // this => graph
          return 'green';
        },
      },
    },
  },
  behaviors: [
    'click-select',
    function () {
      // this => graph
      return {
        type: 'drag-element',
        enable: () => {
          // this.xxx
        },
      };
    },
  ],
});

• Options callback function adds this pointer to Graph

Functions that currently add this pointer: element style mapping, interaction, plugins, data transformation

[Aarebecca]

isObject 无法区分 function 和 object，所以使用 typeof

[Aarebecca]

复杂的泛型传递不利于文档生成和用户查看， 所以改成简单类型