Add tracking issue number for `"vectorcall"` ABI feature #2213

Job	Run time
msrv	52s
rustfmt-clippy	27s
check-cfg	22s
docs	20s
quickchecking	18s
minimal	10s
test (ubuntu-latest, 9.0, 1, 0, 0, 0, 0)	1m 47s
test-book	6s
test-expectations (ubuntu-latest)	42s
test (ubuntu-latest, 9.0, 1, 0, 0, 1, 0)	1m 53s
test-expectations (macos-12)	1m 14s
test (ubuntu-latest, 9.0, 1, 0, 1, 0, 0)	1m 55s
test (ubuntu-latest, 9.0, 1, 0, 1, 1, 0)	2m 6s
test (ubuntu-latest, 9.0, 1, 1, 0, 0, 0)	6m 14s
test (ubuntu-latest, 9.0, 1, 1, 0, 1, 0)	2m 11s
test (ubuntu-latest, 9.0, 1, 1, 1, 0, 0)	3m 12s
test (ubuntu-latest, 9.0, 1, 1, 1, 1, 0)	2m 9s
test (ubuntu-latest, 16.0, 1, 0, 0, 0, 0)	2m 53s
test (ubuntu-latest, 16.0, 1, 0, 0, 1, 0)	2m 33s
test (ubuntu-latest, 16.0, 1, 0, 1, 0, 0)	2m 34s
test (ubuntu-latest, 16.0, 1, 0, 1, 1, 0)	2m 48s
test (ubuntu-latest, 16.0, 1, 1, 0, 0, 0)	2m 55s
test (ubuntu-latest, 16.0, 1, 1, 0, 1, 0)	2m 55s
test (ubuntu-latest, 16.0, 1, 1, 1, 0, 0)	3m 34s
test (ubuntu-latest, 16.0, 1, 1, 1, 1, 0)	3m 4s
test (ubuntu-latest, 16.0, 0, 0, 1)	1m 46s
test (macos-12, 9.0, 0, 0, 0)	1m 19s
success	1s
	52m 20s

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