Add a comment that Rboolean cannot hold NA values. #8085

Job	Run time
MacOS (macOS-13)	47m 34s
MacOS (macOS-14)	22m 58s
Windows (check)	50m 30s
Windows (installer)	19m 59s
Linux (gcc, debian:stable, intel)	33m 17s
Linux (gcc, debian:stable, arm)	30m 17s
Linux (gcc, debian:testing, intel)	33m 20s
Linux (gcc, debian:testing, arm)	31m 11s
Linux (clang, debian:stable, intel)	35m 2s
Linux (clang, debian:stable, arm)	30m 28s
Linux (clang, debian:testing, intel)	34m 10s
Linux (clang, debian:testing, arm)	30m 35s
	6h 39m 21s

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