Feature request: Highlight the flow connector on mouse over #61
Description
When tooltips are enabled, and even without them, it would improve user experience if a connector is highlighted on mouse over.
https://developers.google.com/chart/interactive/docs/gallery/sankey#a-simple-example both nodes and the connector are highlighted on hover.
Code from another plugin to provide some direction on how to implement. I don't think we need to expose anything to config in sankey, in my opinion, it should be "on" by default to improve user experience.
https://www.chartjs.org/chartjs-plugin-annotation/latest/guide/configuration.html#events
https://github.com/chartjs/chartjs-plugin-annotation/blob/0e72ac3d38dcbd0a8cf8beb37d19619a53d2e5a2/src/events.js