Remap `BOOLEAN` to `bool` #114

Job	Run time
check (stable, x86_64-pc-windows-msvc, x86_64-pc-windows-msvc)	21m 44s
check (nightly, x86_64-pc-windows-msvc, i686-pc-windows-msvc)	24m 35s
check (nightly, x86_64-pc-windows-gnu, x86_64-pc-windows-gnu)	33m 0s
check (stable, x86_64-pc-windows-gnu, i686-pc-windows-gnu)	25m 11s
check (stable, x86_64-pc-windows-msvc, aarch64-pc-windows-msvc, --no-run)	21m 20s
check (nightly, x86_64-pc-windows-msvc, aarch64-pc-windows-msvc, --no-run)	26m 14s
	2h 32m 4s

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