enabled and mitigated `-Wdocumentation` and `-Wdocumentation-unknown-command` Clang compiler warnings #1574

Job	Run time
cppcheck	10m 27s
code formatting check	21s
min features with gcc	2m 47s
min features with g++	2m 28s
min features with clang	2m 31s
max features with gcc	3m 36s
max features with g++	2m 3s
max features with clang	2m 48s
max features with gcc and DEBUG	2m 45s
max features with gcc for 32-bit arch (legacy OS)	2m 12s
max features with g++ for 32-bit arch (legacy OS)	2m 6s
max features with clang for 32-bit arch (legacy OS)	2m 3s
	36m 7s

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