revise docs #61

Job	Run time
windows (lua53, lua5.3, 5.3, /mingw64/include/lua5.3/)	3m 53s
unix (5.1, ubuntu-latest)	39s
windows (lua, lua, 5.4, /mingw64/include/)	3m 39s
unix (5.1, macos-latest)	2m 42s
windows (luajit, luajit, 5.1, /mingw64/include/luajit-2.1/)	3m 33s
unix (5.2, ubuntu-latest)	45s
unix (5.2, macos-latest)	1m 35s
unix (5.3, ubuntu-latest)	45s
unix (5.3, macos-latest)	1m 49s
unix (5.4, ubuntu-latest)	37s
unix (5.4, macos-latest)	2m 4s
unix (luajit-2.1.0-beta3, ubuntu-latest)	53s
unix (luajit-2.1.0-beta3, macos-latest)	4m 54s
unix (luajit-openresty, ubuntu-latest)	49s
unix (luajit-openresty, macos-latest)	2m 31s
	31m 8s

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