Small

feat: `associative_vector` rework #140

Job	Run time
Windows-MSVC/2019/Static/X86/Release	2m 29s
Windows-MSVC/2019/Static/X64/Release	2m 43s
Ubuntu/20.04/Static/X64/Release	1m 20s
Ubuntu/22.04/Static/X64/fsanitize	54s
MacOSX/12/Static/X64/Release	1m 5s
	8m 31s

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