Upgrade `trustfall_derive` to `syn` v2. #1104

Job	Run time
Run JS linters	2m 22s
Check rustdoc WASM target	18s
Check fuzz targets	19s
Check lint and rustfmt	1m 59s
Run tests	4m 8s
WASM tests	1m 26s
Python tests and maturin build (3.9)	1m 34s
Python tests and maturin build (3.10)	1m 39s
Python tests and maturin build (3.11)	1m 33s
pre-publish checks	0s
All CI stages	1s
pre-publish checks	0s
publish trustfall_filetests_macros	0s
publish trustfall_core	0s
publish python trustfall	0s
publish trustfall	0s
publish trustfall	0s
publish trustfall_stubgen	0s
	15m 19s

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