[sld-viewer] Highlight buses when hovering

[flo-dup]

Describe the current behavior

the buses can (only) be differentiated with the colors

Describe the expected behavior

the buses can be even more differentiated with the highlight when hovering on one of the color

• in the legend
• in the diagram itself

Describe the motivation

better interactivity, color-blind compatibility

Extra Information

The gif example was achieved with pure CSS, but I had in mind some known limitations on this approach. Either I do recall it wrong, or the navigators have improved their support (the pseudo-selector :has is quite a new feature). The corresponding CSS was:

svg:has(.sld-vl300to500-3:hover) .sld-vl300to500-3:not(.sld-breaker):not(.sld-disconnector) {stroke-width: 5px}

[flo-dup]

Could you first try with pure CSS? before going to mixed javascript / css. If it works we could move this issue to powsybl-diagram in fact.

[flo-dup]

It's probably simpler to do this once powsybl/powsybl-diagram#682 is addressed