Add prettyplease feature to bindgen-cli #2038

Job	Run time
msrv	1m 45s
check-cfg	20s
minimal	16s
docs	23s
quickchecking	20s
rustfmt-clippy	32s
test (ubuntu-latest, 9.0, 1, 0, 0, 0, 0)	2m 25s
test (ubuntu-latest, 9.0, 1, 0, 0, 1, 0)	2m 19s
test-book	18s
test-expectations (ubuntu-latest)	52s
test (ubuntu-latest, 9.0, 1, 0, 1, 0, 0)	1m 42s
test-expectations (macos-latest)	1m 49s
test (ubuntu-latest, 9.0, 1, 0, 1, 1, 0)	2m 1s
test (ubuntu-latest, 9.0, 1, 1, 0, 0, 0)	2m 22s
test (ubuntu-latest, 9.0, 1, 1, 0, 1, 0)	2m 25s
test (ubuntu-latest, 9.0, 1, 1, 1, 0, 0)	2m 23s
test (ubuntu-latest, 9.0, 1, 1, 1, 1, 0)	2m 30s
test (ubuntu-latest, 16.0, 1, 0, 0, 0, 0)	2m 36s
test (ubuntu-latest, 16.0, 1, 0, 0, 1, 0)	3m 21s
test (ubuntu-latest, 16.0, 1, 0, 1, 0, 0)	2m 46s
test (ubuntu-latest, 16.0, 1, 0, 1, 1, 0)	2m 55s
test (ubuntu-latest, 16.0, 1, 1, 0, 0, 0)	3m 21s
test (ubuntu-latest, 16.0, 1, 1, 0, 1, 0)	3m 48s
test (ubuntu-latest, 16.0, 1, 1, 1, 0, 0)	2m 58s
test (ubuntu-latest, 16.0, 1, 1, 1, 1, 0)	3m 7s
test (ubuntu-latest, 16.0, 0, 0, 1)	1m 49s
test (macos-latest, 9.0, 0, 0, 0)	2m 10s
success	1s
	53m 34s

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