[Doc] Split radix_sort doc page into key and key-value API #9229

Job	Run time
clang-format	11s
codespell	17s
PSTL offload cpu,bknd=dpcpp,cmplr=icpx,ubuntu-22.04,std=с++17,cfg=release	8m 10s
documentation	41s
HOST,bknd=omp,cmplr=icpc,macos-11,std=c++17,cfg=release	1s
CPU,bknd=dpcpp,cmplr=icpx,ubuntu-20.04,std=с++17,cfg=release	10m 42s
HOST,bknd=tbb,cmplr=icx-cl,windows-2019,std=c++17,cfg=release	19m 9s
FPGA_EMU,bknd=dpcpp,cmplr=icpx,ubuntu-20.04,std=с++17,cfg=release	9m 23s
HOST,bknd=tbb,cmplr=cl,windows-2019,std=c++17,cfg=release	17m 5s
HOST,bknd=tbb,cmplr=icpx,ubuntu-20.04,std=с++17,cfg=release	12m 8s
CPU,bknd=dpcpp,cmplr=icx,windows-2019,std=c++17,cfg=release	14m 14s
HOST,bknd=omp,cmplr=icpx,ubuntu-20.04,std=с++17,cfg=release	9m 18s
HOST,bknd=omp,cmplr=g++,ubuntu-latest,std=с++17,cfg=release	6m 42s
HOST,bknd=tbb,cmplr=g++,ubuntu-latest,std=с++17,cfg=release	9m 58s
HOST,bknd=tbb,cmplr=g++,ubuntu-20.04,std=с++17,cfg=release	10m 13s
HOST,bknd=tbb,cmplr=clang++,ubuntu-20.04,std=с++17,cfg=release	11m 16s
HOST,bknd=omp,cmplr=clang++,ubuntu-20.04,std=с++17,cfg=release	8m 35s
HOST,bknd=tbb,cmplr=clang++,ubuntu-latest,std=с++17,cfg=release	11m 23s
HOST,bknd=tbb,cmplr=icpx,ubuntu-20.04,std=с++17,cfg=release	12m 7s
HOST,bknd=serial,cmplr=g++,ubuntu-20.04,std=с++17,cfg=release	5m 14s
	2h 56m 47s

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