Allow custom derives on new-type alias #1998

Job	Run time
msrv	1m 38s
docs	18s
check-cfg	24s
minimal	14s
quickchecking	14s
rustfmt-clippy	29s
test-book	5s
test-expectations (ubuntu-latest)	50s
test-expectations (macos-latest)	1m 54s
test (ubuntu-latest, 9.0, 1, 0, 0, 0, 0)	1m 57s
test (ubuntu-latest, 9.0, 1, 0, 0, 1, 0)	1m 53s
test (ubuntu-latest, 9.0, 1, 0, 1, 0, 0)	2m 18s
test (ubuntu-latest, 9.0, 1, 0, 1, 1, 0)	1m 49s
test (ubuntu-latest, 9.0, 1, 1, 0, 0, 0)	3m 13s
test (ubuntu-latest, 9.0, 1, 1, 0, 1, 0)	2m 11s
test (ubuntu-latest, 9.0, 1, 1, 1, 0, 0)	2m 18s
test (ubuntu-latest, 9.0, 1, 1, 1, 1, 0)	2m 29s
test (ubuntu-latest, 16.0, 1, 0, 0, 0, 0)	2m 51s
test (ubuntu-latest, 16.0, 1, 0, 0, 1, 0)	2m 46s
test (ubuntu-latest, 16.0, 1, 0, 1, 0, 0)	2m 35s
test (ubuntu-latest, 16.0, 1, 0, 1, 1, 0)	2m 37s
test (ubuntu-latest, 16.0, 1, 1, 0, 0, 0)	3m 31s
test (ubuntu-latest, 16.0, 1, 1, 0, 1, 0)	2m 58s
test (ubuntu-latest, 16.0, 1, 1, 1, 0, 0)	3m 2s
test (ubuntu-latest, 16.0, 1, 1, 1, 1, 0)	2m 56s
test (ubuntu-latest, 16.0, 0, 0, 1)	1m 49s
test (macos-latest, 9.0, 0, 0, 0)	1m 25s
success	2s
	50m 46s

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