Update utf8.h #36

Job	Run time
build (ubuntu-latest, Debug, address)	13s
build (ubuntu-latest, Debug, memory)	15s
build (ubuntu-latest, Debug, undefined)	14s
build (ubuntu-latest, RelWithDebInfo, address)	15s
build (ubuntu-latest, RelWithDebInfo, memory)	17s
build (ubuntu-latest, RelWithDebInfo, undefined)	19s
build (ubuntu-latest, MinSizeRel, address)	16s
build (ubuntu-latest, MinSizeRel, memory)	26s
build (ubuntu-latest, MinSizeRel, undefined)	16s
build (ubuntu-latest, Release, address)	18s
build (ubuntu-latest, Release, memory)	16s
build (ubuntu-latest, Release, undefined)	15s
build (macOS-latest, Debug, address)	12s
build (macOS-latest, Debug, undefined)	11s
build (macOS-latest, RelWithDebInfo, address)	9s
build (macOS-latest, RelWithDebInfo, undefined)	12s
build (macOS-latest, MinSizeRel, address)	12s
build (macOS-latest, MinSizeRel, undefined)	12s
build (macOS-latest, Release, address)	12s
build (macOS-latest, Release, undefined)	15s
	4m 55s

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