Feature request: highlight node and its links on hover

[shinglyu]

When exploring the graph, it would be useful to hover over a node to highlight its links. Currently only the selected node is highlighted. I'd like to be able to hover over any node and highlight is link.

Even cooler if we can highlight the seconday links and so on in different gradients. For example

flowchart LR
Selected --very very thick link--> node1
node1 --very thick link--> node2
node2 -- thick link --> node3
node3 -- normal link --> node4

Selected --very very thick link--> node5
node5 --very thick link--> node6
node6 -- thick link --> node7
node7 -- normal link --> node8
node9 -- normal link --> node10