[reggen] Describe REGWEN properly for multi-registers #3643

Job	Run time
Lint (quick)	3m 5s
Build documentation	9m 38s
Run OTBN smoke Test	2m 51s
Airgapped build	8m 13s
Run OTBN crypto tests	3m 25s
Lint (slow)	11m 50s
Verible lint	0s
Verilated English Breakfast	8m 15s
CW305's Bitstream	23m 23s
Verilated Earl Grey	1h 20m 22s
Build Docker Containers	2m 33s
Build and test software	16m 9s
Earl Grey for CW310 / Build bitstream	1h 9m 58s
Earl Grey for CW310 Hyperdebug / Build bitstream	1h 15m 21s
Earl Grey for CW340 / Build bitstream	1h 28m 34s
CW310 Test ROM Tests / FPGA test	6m 3s
CW310 ROM Tests / FPGA test	40m 53s
CW310 ROM_EXT Tests / FPGA test	7m 23s
CW310 SiVal ROM_EXT Tests / FPGA test	39m 29s
CW310 Manufacturing Tests / FPGA test	35m 25s
CW310 SiVal Tests / FPGA test	26m 43s
Cache bitstreams to GCP	3m 23s
CW340 Test ROM Tests / FPGA test	4m 24s
CW340 ROM_EXT Tests / FPGA test	7m 16s
CW340 ROM Tests / FPGA test	1m 12s
CW340 SiVal Tests / FPGA test	19m 27s
CW340 Manufacturing Tests / FPGA test	8m 35s
CW340 SiVal ROM_EXT Tests / FPGA test	5m 25s
Verify FPGA jobs	21s
	10h 9m 36s

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