doc: Fix typo in `build-unix.md` #3043

Job	Run time
macOS 13 native, x86_64, no depends, sqlite only, gui	59m 51s
Win64 native, VS 2022	2h 33m 17s
test each commit	0s
ASan + LSan + UBSan + integer, no depends, USDT	1h 0m 32s
	4h 33m 40s

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