remove smartquotes in C comment (#353) #297

Job	Run time
Build and test on x86	30s
Build and test on x64	30s
Build and test on armv7	2m 8s
Build and test on aarch64	2m 40s
Build and test on riscv32 with extensions	2m 28s
Build and test on riscv64	2m 19s
Build and test on armt2	2m 4s
Build and test on riscv32	2m 44s
Build and test on riscv64 with extensions	2m 12s
Build and test on loongarch64	2m 2s
Build and test on s390x	2m 7s
	21m 44s

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