Fix array declaration syntax in C example (#562) #401

Job	Run time
windows-msvc-shared (MSGPACK)	4m 7s
windows-msvc-shared (AVRO)	7m 11s
windows-msvc-shared (CAPNPROTO)	7m 49s
windows-msvc-shared (PARQUET)	38m 54s
windows-msvc-shared (FLEXBUFFERS)	5m 47s
windows-msvc-shared (TOML)	4m 20s
windows-msvc-shared (JSON)	11m 11s
windows-msvc-shared (UBJSON)	8m 1s
windows-msvc-shared (YAML)	4m 20s
windows-msvc-shared (XML)	3m 52s
windows-msvc-shared (CBOR)	8m 33s
windows-msvc (CBOR)	35s
windows-msvc (TOML)	33s
windows-msvc (AVRO)	36s
windows-msvc (UBJSON)	35s
windows-msvc (YAML)	36s
windows-msvc (FLEXBUFFERS)	35s
windows-msvc (JSON)	35s
windows-msvc (MSGPACK)	35s
windows-msvc (CAPNPROTO)	35s
windows-msvc (PARQUET)	35s
windows-msvc (XML)	35s
windows-msvc (benchmarks)	33s
	1h 51m 3s

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