[refactor] #3682: Remove all direct dependencies on syn 1

[DCNick3]

Description

This concludes the syn 2 migration saga, removing all mentions of it from the codebase. It also removes the syn2 renaming of the new version, as we are no longer depending on two versions at the same time.

We still have syn 1 as a transitive dependency on syn 1 though =(

I suggest reviewing the two commits separately, as the blank rename of syn2 to syn is very noisy

Linked issue

Closes #3682

Benefit

Less complexity due to use of multiple versions of the same library; only the shiny new API.

Checklist

• make CI pass

[coveralls]

Pull Request Test Coverage Report for Build 8232887369

Details

• 323 of 404 (79.95%) changed or added relevant lines in 36 files are covered.
• 4017 unchanged lines in 71 files lost coverage.
• Overall coverage decreased (-0.05%) to 56.737%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
ffi/derive/src/attr_parse/getset.rs	8	9	88.89%
ffi/derive/src/wrapper.rs	20	21	95.24%
primitives/derive/src/socket_addr.rs	9	10	90.0%
schema/derive/src/lib.rs	23	24	95.83%
smart_contract/derive/src/lib.rs	0	1	0.0%
smart_contract/trigger/derive/src/lib.rs	0	1	0.0%
torii/derive/src/lib.rs	3	4	75.0%
wasm_codec/derive/src/lib.rs	39	40	97.5%
macro/utils/src/lib.rs	9	11	81.82%
smart_contract/executor/derive/src/validate.rs	2	4	50.0%

Files with Coverage Reduction	New Missed Lines	%
wasm_codec/derive/src/lib.rs	1	82.15%
macro/utils/src/lib.rs	1	58.21%
tools/kagami/src/crypto.rs	1	12.12%
ffi/derive/src/impl_visitor.rs	1	77.91%
primitives/src/lib.rs	1	0.0%
core/src/sumeragi/network_topology.rs	1	98.78%
primitives/src/unique_vec.rs	2	91.24%
data_model/src/metadata.rs	2	78.87%
config/src/kura.rs	3	80.0%
config/src/logger.rs	5	72.73%

Totals
Change from base Build 7884695009:	-0.05%
Covered Lines:	22427
Relevant Lines:	39528

---

💛 - Coveralls