Warn about the correct usage of `discrete_space` #1604

Job	Run time
id_repo	1s
lint	10s
docker-build (oldest, cpu)	37m 3s
docker-build (oldest, hip)	1h 15m 34s
docker-build (latest, cpu)	31m 35s
docker-build (latest, cuda)	59m 57s
docker-build (latest, hip)	1h 12m 25s
clang-tidy-test	12m 26s
test (oldest, cpu-gcc, 17, Debug)	11m 49s
test (oldest, cpu-gcc, 17, Release)	11m 51s
test (oldest, cpu-gcc, 20, Debug)	11m 17s
test (oldest, cpu-gcc, 20, Release)	12m 20s
test (oldest, cpu-clang, 17, Debug)	8m 50s
test (oldest, cpu-clang, 17, Release)	10m 47s
test (oldest, hip, 17, Debug)	29m 23s
test (oldest, hip, 17, Release)	24m 48s
test (oldest, hip, 20, Debug)	29m 14s
test (oldest, hip, 20, Release)	25m 22s
test (latest, cpu-gcc, 17, Debug)	10m 24s
test (latest, cpu-gcc, 17, Release)	9m 55s
test (latest, cpu-gcc, 20, Debug)	12m 59s
test (latest, cpu-gcc, 20, Release)	10m 36s
test (latest, cpu-gcc, 23, Debug)	11m 16s
test (latest, cpu-gcc, 23, Release)	10m 41s
test (latest, cpu-clang, 17, Debug)	7m 23s
test (latest, cpu-clang, 17, Release)	11m 18s
test (latest, cpu-clang, 20, Debug)	8m 49s
test (latest, cpu-clang, 20, Release)	11m 20s
test (latest, cpu-clang, 23, Debug)	9m 37s
test (latest, cpu-clang, 23, Release)	12m 44s
test (latest, cuda, 17, Debug)	27m 43s
test (latest, cuda, 17, Release)	27m 48s
test (latest, hip, 17, Debug)	27m 27s
test (latest, hip, 17, Release)	24m 14s
test (latest, hip, 20, Debug)	30m 37s
test (latest, hip, 20, Release)	25m 59s
test (latest, hip, 23, Debug)	32m 5s
test (latest, hip, 23, Release)	26m 45s
	13h 34m 32s

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