der_derive: add workaround for `syn` v2.0.73 #3035

Job	Run time
build (1.72.0, thumbv7em-none-eabi)	37s
minimal-versions	0s
build (1.72.0, wasm32-unknown-unknown)	36s
test (1.72.0)	1m 15s
test (stable)	1m 12s
build (stable, thumbv7em-none-eabi)	33s
build (stable, wasm32-unknown-unknown)	36s
	4m 49s

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