Fix some minor inconsistencies in the manual (#3820) #141

Job	Run time
doctest (1.10, ubuntu-latest)	27m 18s
test (1.6, short, ubuntu-latest)	1h 6m 14s
doctest (1.11-nightly, ubuntu-latest)	28m 5s
test (1.6, long, ubuntu-latest)	39m 4s
doctest (nightly, ubuntu-latest)	27m 17s
test (1.10, short, ubuntu-latest)	50m 41s
doctest (1.10, ubuntu-latest, depwarn=error)	27m 8s
test (1.10, long, ubuntu-latest)	34m 20s
doctest (1.10, macOS, RPTU)	1s
test (1.11-nightly, short, ubuntu-latest)	57m 44s
test (1.11-nightly, long, ubuntu-latest)	32m 26s
test (nightly, short, ubuntu-latest)	1h 3m 43s
test (nightly, long, ubuntu-latest)	37m 3s
test (1.10, short, ubuntu-latest, depwarn=error)	50m 30s
test (1.10, long, ubuntu-latest, depwarn=error)	31m 25s
test (1.10, short, macOS, RPTU)	1s
test (1.10, long, macOS, RPTU)	1s
test (1.10, book, ubuntu-latest)	31m 47s
	10h 4m 48s

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