randomLineString does not take max_rotation option into account

It seems to be related to the fact that the previous angle variable is actually a local variable of the inner loop over the vertices so that it is incorrectly reset at each vertex. Here is a suggested modification of the code, which also appears to be more simple:

for (var i = 0; i < count; i++) {
    var startingPoint = turf.randomPosition(bbox);
    var vertices = [startingPoint];
    var priorAngle = Math.random() * 2 * Math.PI;
    for (var j = 0; j < num_vertices - 1; j++) {
        var angle = priorAngle + (Math.random() - 0.5) * max_rotation * 2;
        priorAngle = angle;
        var distance = Math.random() * max_length;
        vertices.push([
            vertices[j][0] + distance * Math.cos(angle),
            vertices[j][1] + distance * Math.sin(angle),
        ]);
    }
    features.push(turf.lineString(vertices));
}

I would be pleased to try to create a PR if you think this fix is correct, althought it might take some time to me for a first contribution to study how to write a relevent test, update the build, etc.

Start in packages/turf-random/index.ts around line 237 and inspect how randomLineString handles max_rotation and the prior angle. Add a regression test covering max_rotation, then run the relevant package tests and update the build if required; done means the option affects successive vertices as described.