Add `ExpandAttribute` handler #7397

Job	Run time
build test linux x86-64	3m 44s
build test windows x86-64	13m 46s
check-rust	2m 0s
check-website	10s
scarb-metadata compatibility check	49s
doc tests	3m 22s
test linux x86-64 1/8	16m 2s
test linux x86-64 2/8	16m 58s
test linux x86-64 3/8	15m 10s
test linux x86-64 4/8	12m 42s
test linux x86-64 5/8	12m 18s
test linux x86-64 6/8	9m 22s
test linux x86-64 7/8	9m 38s
test linux x86-64 8/8	10m 31s
test windows x86-64 1/8	14m 4s
test windows x86-64 2/8	16m 41s
test windows x86-64 3/8	13m 57s
test windows x86-64 4/8	13m 7s
test windows x86-64 5/8	11m 11s
test windows x86-64 6/8	9m 43s
test windows x86-64 7/8	8m 15s
test windows x86-64 8/8	10m 8s
	3h 43m 38s

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