Add doc for spin data format #7507

Job	Run time
Test Python (1, 3.8)	12m 37s
Test Python (1, 3.11)	11m 27s
Test Python (2, 3.8)	10m 11s
Test Python (2, 3.11)	10m 7s
Test Python (3, 3.8)	10m 30s
Test Python (3, 3.11)	10m 11s
Test Python (4, 3.8)	10m 9s
Test Python (4, 3.11)	9m 14s
Test Python (5, 3.8)	10m 43s
Test Python (5, 3.11)	10m 17s
Test Python (6, 3.8)	11m 0s
Test Python (6, 3.11)	10m 43s
Combine and update integration test durations (3.8)	9s
Combine and update integration test durations (3.11)	7s
Pass testing Python	3s
	2h 7m 28s

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