Fix format_to + FMT_STRING for wide character type #6005

Job	Run time
mingw (mingw64)	3m 48s
build (windows-2019, Win32, v142, 17, Debug)	1m 39s
mingw (ucrt64)	3m 53s
build (windows-2019, Win32, v142, 17, Release)	2m 5s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	1m 6s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	3m 5s
build (windows-2019, x64, v140, 14, Debug)	1m 21s
build (windows-2019, x64, v140, 14, Release)	2m 5s
build (windows-2019, x64, v141, 17, Debug)	1m 45s
build (windows-2019, x64, v141, 17, Release)	2m 35s
build (windows-2019, x64, v142, 17, Debug)	1m 40s
build (windows-2019, x64, v142, 17, Release)	2m 19s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	1m 31s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	2m 36s
build (windows-2019, x64, v142, 20, Debug)	1m 27s
build (windows-2019, x64, v142, 20, Release)	2m 51s
build (windows-2022, x64, v143, Debug, 20)	1m 42s
	37m 28s

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