tools/plugin: Fix broken README.md formatting #20045

Job	Run time
manifest-check	1m 3s
build-windows (mtl lnl)	7m 23s
LP64-WIP	3m 59s
build-windows (imx8 imx8x imx8m imx8ulp)	8m 29s
build-windows (tgl tgl-h)	6m 45s
build-linux (mnfst, tgl tgl-h)	5m 26s
build-linux (-d, mnfst, lnl)	4m 28s
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	7m 19s
build-linux (mnfst, ptl)	4m 35s
build-linux (mnfst, --all)	13m 47s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	6m 14s
build-linux (mnfst, mtl lnl)	6m 17s
build-linux (zmain, tgl tgl-h)	6m 17s
build-windows (-d, lnl)	6m 33s
build-linux (zmain, mtl lnl)	5m 37s
build-linux (zmain, ptl)	4m 24s
build-windows (ptl)	6m 20s
compare-linux-win	30s
	1h 45m 26s

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