Add the "green tick" visual indicator to show milestones met in Gantt charts Merged

In Gantt charts, the "green tick" provides visual indication that a phase has been completed.

However, it is not possible to see a "green tick" for milestones that have been met.

It's a tiny thing, but a visual indicator of progress through a milestone would be great for folks less involved in a project to quickly see the overall status of a project and know that a milestone has been met and not skipped or missed.