docs(README): add #anchor and improve `note`s #301

Job	Run time
build (18.x, ubuntu-latest, bash)	45s
build (18.x, macos-latest, bash)	34s
build (18.x, windows-latest, bash)	1m 17s
build (18.x, windows-latest, powershell)	1m 19s
build (20.x, ubuntu-latest, bash)	45s
build (20.x, macos-latest, bash)	52s
build (20.x, windows-latest, bash)	1m 27s
build (20.x, windows-latest, powershell)	1m 32s
build (21.x, ubuntu-latest, bash)	49s
build (21.x, macos-latest, bash)	36s
build (21.x, windows-latest, bash)	1m 20s
build (21.x, windows-latest, powershell)	1m 14s
	12m 30s

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