Highlight edges through dispatchAction in force-layout graph

### What problem does this feature solve?
In my project, I want to highlight one or some paths (including several edges). However we can only highlight nodes (dataIndex or data name) through dispatchAction. Could you please add some new feature to help to highlight the edges through dispatchAction?

### What does the proposed API look like?
```javascript
myChart.dispatchAction({
type: 'highlight',
seriesIndex: 0,
seriesName: 'test',
edgeDataIndex: number | list
});
```