enabled and mitigated `-Wdocumentation` and `-Wdocumentation-unknown-command` Clang compiler warnings #1573

Job	Run time
code formatting check	17s
min features with gcc	2m 56s
cppcheck	10m 50s
min features with g++	2m 32s
min features with clang	2m 20s
max features with gcc	4m 51s
max features with g++	2m 49s
max features with clang	2m 37s
max features with gcc and DEBUG	2m 53s
max features with gcc for 32-bit arch (legacy OS)	2m 21s
max features with g++ for 32-bit arch (legacy OS)	1m 50s
max features with clang for 32-bit arch (legacy OS)	2m 21s
	38m 37s

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