Add `ExpandAttribute` handler #7612

Job	Run time
check-rust	3m 39s
check-website	8s
build test linux x86-64	3m 28s
scarb-metadata compatibility check	39s
build test windows x86-64	9m 2s
doc tests	3m 12s
test linux x86-64 1/8	15m 38s
test linux x86-64 2/8	17m 18s
test linux x86-64 3/8	13m 54s
test linux x86-64 4/8	13m 15s
test linux x86-64 5/8	11m 27s
test linux x86-64 6/8	9m 44s
test linux x86-64 7/8	9m 43s
test linux x86-64 8/8	10m 47s
test windows x86-64 1/8	14m 31s
test windows x86-64 2/8	15m 42s
test windows x86-64 3/8	13m 46s
test windows x86-64 4/8	11m 27s
test windows x86-64 5/8	11m 37s
test windows x86-64 6/8	9m 13s
test windows x86-64 7/8	9m 22s
test windows x86-64 8/8	9m 52s
	3h 37m 24s

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