River, you can see in the video that each monk started converting a brief moment after the one before.
This is very typical when you have your monks numbered under control groups 2-3-4-5-6-7-8.
He sees your woads and simply taps those numbers, and then the woads.
If he was using a monk macro, all the monks would start converting at the same time, and then they would start deselecting to target different units. This would appear as all monks facing one direction and waving, and then suddenly one by one facing different directions.
It is very very clear that it was just numbered monks 11