Remove `fmt/core.h` from docs (#4421) #8130

Job	Run time
mingw (ucrt64)	3m 57s
mingw (mingw64)	3m 53s
build (windows-2019, Win32, v142, 17, Release)	2m 37s
build (windows-2019, x64, v141, 14, Release)	2m 26s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	1m 5s
build (windows-2019, x64, v141, 17, Release)	2m 10s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	1m 51s
build (windows-2019, x64, v141, 17, Debug)	1m 19s
build (windows-2019, x64, v141, 14, Debug)	1m 18s
build (windows-2019, x64, v142, 17, Release)	2m 15s
build (windows-2019, x64, v142, 20, Release)	3m 21s
build (windows-2019, x64, v142, 17, Debug)	1m 15s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	2m 26s
build (windows-2022, x64, v143, Debug, 20)	1m 38s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	1m 56s
build (windows-2019, x64, v142, 20, Debug)	1m 29s
build (windows-2019, Win32, v142, 17, Debug)	1m 11s
	36m 7s

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