Fixing warning in command SubtractAssetQuantity, removing unnecessarily includes, small documentation change #3155

Job	Run time
Pull requests from forks should use other workflow	2s
pr_comment_reaction_rocket	0s
Check if github workflows were properly made from sources	12s
generate_matrixes	5s
prepare-macos-env	5s
Docker-iroha-builder	3m 24s
prepare-windows-env	4s
build-M (macos clang Debug normal)	2h 20m 40s
build-M (macos clang Release normal)	1h 40m 3s
build-M (macos gcc-10 Debug normal)	1h 52m 0s
build-M (macos gcc-10 Release normal)	1h 18m 56s
build-W	0s
build-UR (ubuntu gcc-9 Release burrow)	30m 39s
build-UD (ubuntu clang-10 Debug burrow)	27m 47s
build-UR (ubuntu gcc-9 Release normal)	49m 51s
build-UD (ubuntu clang-10 Debug normal)	50m 27s
build-UR (ubuntu gcc-9 Release ursa)	51m 9s
build-UD (ubuntu clang-10 Debug ursa)	50m 51s
build-UR (ubuntu gcc-10 Release burrow)	30m 25s
build-UD (ubuntu gcc-9 Debug burrow)	30m 23s
build-UR (ubuntu gcc-10 Release normal)	49m 17s
build-UD (ubuntu gcc-9 Debug normal)	1h 0m 36s
build-UR (ubuntu gcc-10 Release ursa)	49m 4s
build-UD (ubuntu gcc-9 Debug ursa)	1h 0m 21s
build-UD (ubuntu gcc-10 Debug burrow)	28m 53s
build-UD (ubuntu gcc-10 Debug normal)	56m 7s
build-UD (ubuntu gcc-10 Debug ursa)	57m 56s
docker-R	0s
docker-D	0s
	18h 39m 17s

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