Add lane highlight to Speed Limits tool

[originalfoo]

When user is hovering a speed limit icon, particularly in lane-wise mode which allows per-lane speed setting, it is sometimes unclear which lane it corresponds to.

Could we pimp the relevant lane with a highlight to make it completely clear which lane is being altered?

The lane highlight would only be visible while the speed limit icon is hovered.

Suggestion: White highlight (like outgoing lanes on Lane Connector tool) but without the border -a subtle highlight might be sufficient.

[kvakvs]

This might take more thinking.
I.e. those overlay signs should behave more like UI elements with the following properties:

• Change rendering slightly when they become UI elements (optional)
• Change color/brightness slightly when the mouse is hovered above them. Render an outline maybe.
• Actively resist overlapping other signs, sliding away along the road segment vector if too many signs were squeezed together. Or optionally just push them apart in some cheap algorithm, and use thin lines to visually connect them to their lanes.

Now that users will perceive them as UI elements, also add the suggestion from this ticket with lane highlights.

[originalfoo]

I find overlapping speed signs to be hugely useful timesaver - I can click overlap and update both directions at same time. I use that little trick constantly.

I think all our overlays are going to need a few iterations to improve aesthetics and usability. But for now I think just getting lane highlight solves the biggest issue of it not being overtly clear which lane/direction is being affected (especially on roads with large numbers of lanes).

[originalfoo]

Refs: #33

[kianzarrin]

Oops I added lane highlight to parking tool by mistake!:

clicking enlarges the overlay turning it into orange.

Holding shift highlights all the lanes blue (orange if clicked). I don't know how to take a screenshot of that though. Its a nice visual feedback though.

[originalfoo]

Noce lol. I forgot that parking tool had Shift modifier to apply to route so that too will benefit from lane highlight! Keep it :)

[kianzarrin]

Noce lol. I forgot that parking tool had Shift modifier to apply to route so that too will benefit from lane highlight! Keep it :)

I need to add tooltip hotkey
its blocked by #701