Shortcut for creating a path following an existing path

[jidanni]

Here we see we've already followed this path on the left node and we still want to hit the center node and then the right node to complete following this path.

But wouldn't it be great if we could just hit the right node and then the center node would also become part of our new path automatically?

So we need to a way of telling Vespucci that we want to include all the intermediate nodes.

(Why would we be doing this? Because let's say there is a boundary, or a fence, that happens to share the same path as an existing path. But we still need to make it an independent feature, and not just add more tags to the existing path.)

And of course, sometimes we don't want to include all the intermediate nodes. So this new enhancement idea needs to be some kind of toggle option...

And of course we don't necessarily want to include the entire existing path, just up to the point where we want to stop and turn away.

See also openstreetmap/iD#9368 .