doc fix: remove extra 'we' in designdecisions (#4199) #16924

Job	Run time
doctest (1.10, ubuntu-latest)	31m 21s
test (1.6, short, ubuntu-latest)	1h 33m 47s
doctest (1.11-nightly, ubuntu-latest)	29m 34s
test (1.6, long, ubuntu-latest)	54m 14s
doctest (nightly, ubuntu-latest)	42m 56s
test (1.10, short, ubuntu-latest)	1h 15m 20s
doctest (1.10, ubuntu-latest, depwarn=error)	31m 0s
test (1.10, long, ubuntu-latest)	45m 8s
doctest (1.10, macOS, RPTU)	12m 25s
test (1.11-nightly, short, ubuntu-latest)	1h 26m 3s
test (1.11-nightly, long, ubuntu-latest)	53m 36s
test (nightly, short, ubuntu-latest)	1h 46m 26s
test (nightly, long, ubuntu-latest)	58m 11s
test (1.10, short, ubuntu-latest, depwarn=error)	1h 10m 16s
test (1.10, long, ubuntu-latest, depwarn=error)	46m 33s
test (1.10, short, macOS, RPTU)	13m 44s
test (1.10, long, macOS, RPTU)	14m 5s
test (1.10, book, ubuntu-latest)	52m 39s
test (nightly, book, ubuntu-latest)	32m 48s
	15h 50m 6s

Provide feedback